Crushers for mineral materials or recycled materials

Description

[0001] The invention relates to a crusher for mineral materials or recycled materials, in particular rotary impact crushers, jaw crushers, cone crushers or roller crushers, with a crushing unit comprising a first crushing element, in particular a rotor or a crushing jaw, wherein a second movable crushing element, in particular an impact rocker or a crushing jaw, is associated with the first crushing element, wherein a crushing gap is formed between the crushing elements, wherein a hydraulic cylinder is coupled to one of the crushing elements, which is arranged and designed to allow a movement of the coupled crushing element that increases the width of the crushing gap in an evasive movement, wherein a pressure chamber of the hydraulic cylinder is connected to a pressure chamber of a pressure relief valve of an overload release device, wherein a piston of the pressure relief valve is adjustable in a cylinder between a closed position and an open position.wherein in the closed position a fluid-conducting connection between the pressure chamber and a pressure equalization area is blocked and in the open position the fluid-conducting connection is at least partially released, and wherein the piston has at least one piston pressure surface by means of which the piston limits the pressure chamber in the closed position transversely to the direction of movement of the piston.

[0002] From DE 10 2017 002 079 B4, an impact crusher is known in which a variable crushing gap is set between a rotatable rotor and an impact arm. In normal crushing operation, the material to be crushed is fed to the rotor via a material feed. The rotor throws this material against the impact arm. The forces generated cause the rock material to break. The rock material is thus crushed to the desired grain size and can fall out of the crusher housing through the crushing gap. However, it can happen that non-crushable objects are fed to the rotor. These could, for example, be iron parts. This represents a critical overload situation for the impact crusher. In particular, there is a risk of damage to the crusher. To manage such an overload situation, a piston-cylinder unit is coupled to the impact arm.This allows the position of the impact arm, and thus the width of the crushing gap, to be changed. The piston-cylinder unit includes a gas spring against which the impact arm is supported.

[0003] In normal crushing operation, the width of the crushing gap is adjusted to the desired dimension. In critical overload situations, the gas spring can be compressed, causing the impact arm to deflect. This allows the crushing gap to be increased abruptly. The unbreakable object can then fall out of the crushing gap. The width of the crushing gap is then readjusted to the desired dimension.

[0004] The gas spring proposed in DE 10 2017 002 079 B4 introduces elasticity into the support of the impact arm. During crushing operations, the forces vary within a certain permissible range due to the different hardness and size of the rock fragments. In response to these changing forces, the elastic gas spring causes a constant variation in the crushing gap and thus in the grain size of the crushed material, which is undesirable.

[0005] From EP 0 019 541 B1, an impact crusher is known in which the crushing gap can be adjusted via a hydraulic cylinder. The hydraulic cylinder has a piston to which a piston rod is coupled. The piston is adjustable within a cylinder chamber. The piston rod is connected to the impact arm. An overload valve is provided in case of an overload situation. If an unbreakable object enters the crushing chamber, the overload valve is triggered. This increases the crushing gap, allowing the unbreakable object to fall out of the crushing chamber.

[0006] In crushers, particularly rotary impact crushers, it is often the case, as already indicated above, that rock material of varying sizes and hardness is fed into the crushing unit during normal crushing operation. These rock materials are manageable for the rotary impact crusher and can be crushed. Therefore, such a non-critical case must be distinguished from a critical overload situation in which an unbreakable object enters the crushing unit. The method known from EP 0 019 541 B1 is suitable for slow-running crusher variants. Here, the machine components for adjusting the crushing gap, as well as the piston rod of the hydraulic cylinder, must be moved until the fluid compression creates a chamber pressure that triggers the pressure relief valve.It is obvious that the set pressure of the pressure relief valve must not be too low, as otherwise normal crusher loads would cause the crushing gap to shift, resulting in significant quality losses of the final material. High-speed crusher variants require a rapid opening of the crushing gap. Accordingly, the pressure relief valve must be able to react quickly and simultaneously be adequately sized to limit the pressure increase caused by the rapidly accelerating machine components during the adjustment of the crushing gap.

[0007] Other crushers with overload release devices are known from EP 3 919 177 B1, EP 2 774 681 B1 and US 2015 / 0224508 A1.

[0008] The object of the invention is to provide a crusher of the type mentioned above in which the overload release device responds quickly in the event of an overload, and in which, at the same time, the crushing gap is kept as constant as possible during normal operation.

[0009] This problem is solved by ensuring that, in the closed state of the pressure relief valve, the projection of the piston pressure surface or the piston pressure surfaces of the piston into a projection plane transverse to the direction of movement of the piston, in particular perpendicular to the direction of movement of the piston, only limits a part of the pressure chamber transverse to the direction of movement of the piston.

[0010] This solution reduces the piston pressure area(s) and thus the effective area(s) over which a force is applied to adjust the piston and thereby trigger the pressure relief valve, compared to prior art solutions. These smaller areas result in lower holding forces, which can then be more easily supported. In other words, manageable forces are generated at the piston, which can be easily absorbed outside the pressure chamber of the pressure relief valve to keep the valve closed during normal crusher operation. Additionally, this design reduces the mass of the piston and thus the mass of the accelerated components of the pressure relief valve. This significantly improves the response in overload situations.

[0011] A pressure relief valve according to the invention can be designed such that several piston pressure surfaces are present on the piston, which then, in a projection plane transverse to the piston's direction of movement, only delimit a portion of the pressure chamber transverse to the piston's direction of movement. The multiple piston pressure surfaces need not all be located in the same plane on the piston. It is also conceivable that the piston pressure surfaces have different shapes.

[0012] According to a preferred embodiment of the invention, a bridging device may be provided with respect to which the piston is adjustable, the bridging device having at least one pressure surface section that delimits the pressure chamber in the closed state transversely to the piston's positioning direction, and a projection of the pressure surface section(s) in the direction of the piston's positioning movement into the projection plane, particularly the closing plane, does not completely or at all cover the piston pressure surface(s). This results in a simple design.

[0013] The bridging device can be designed in particular in the form of a projection, preferably in the form of a mandrel.

[0014] It is possible that the piston pressure surface(s) extend only over a portion of the pressure chamber's cross-sectional area, perpendicular to the piston's direction of movement. The remaining cross-sectional area of ​​the pressure chamber may then be limited by the pressure surface section(s) of the bridging device.

[0015] Preferably, the bridging device is arranged in a fixed position in or on the cylinder.

[0016] It is also conceivable that the bridging device is movable relative to the piston. For example, the bridging device could be attached in such a way that it is movable in the direction of the piston's adjustment movement and / or transversely to the direction of the piston's adjustment movement.

[0017] It is further preferably possible that the pressure surface section of the bridging device is arranged centrally within the pressure chamber, wherein an annular space is preferably formed between the radially outer boundary wall of the pressure chamber and the associated outer circumference of the pressure surface section, within which the piston is adjustable.

[0018] If it is intended that the surface normals point in the same direction to the projections of the piston pressure surface(s) and the pressure surface section(s), then the bridging device can simply be assigned to the pressure chamber of the pressure relief valve.

[0019] A crusher according to the invention can, for example, be designed such that the bridging device is connected to the cylinder(s) of the pressure relief valve by means of a connecting section, in particular in a fixed or movably connected manner, that the bridging device holds a head on a support inside the cylinder, and that the head forms or supports at least one pressure surface section. The loads acting in the pressure chamber can be safely transferred via the head and the connecting section. It is conceivable that the head and / or the connecting section form a guide for the piston, which is in particular designed in the shape of a sleeve. This reduces the number of parts.

[0020] A particularly preferred embodiment of the invention is such that the piston has a cylindrical outer wall by means of which it faces the inner wall of the cylinder that forms the pressure chamber, and that the piston is annular in shape and has a preferably cylindrical inner wall. The piston is then designed as a preferably sleeve-shaped component. Due to this design, the piston can be made relatively lightweight yet stable. The end of the piston associated with the pressure chamber can then at least partially form the piston pressure surface. In other words, the sleeve end face can at least partially form the piston pressure surface(s).

[0021] A particularly preferred embodiment of the invention is such that the piston is supported by a support section outside the pressure chamber against a spring, the spring applying a preload force to the piston in the direction of the piston's closing position to bias the piston against a valve seat. This ensures reliable positioning of the piston in the closed position with manageable spring forces. Simultaneously, it enables a quick return of the piston after an overload situation has ceased in a technically simple manner. The spring can be a mechanical element, for example, a coil spring or a disc spring. It is also conceivable that the spring is formed by a fluid system, in particular a hydraulic system. This hydraulic system could include the hydraulic cylinder, in particular the space within the hydraulic cylinder that accommodates the piston rod.It is conceivable that the spring is formed from several spring elements.

[0022] A particularly preferred embodiment of the invention is such that the piston separates a low-pressure area of ​​the pressure relief valve from the pressure chamber, and that, when the piston is moved from the closed to the open position, an actuating section is located within this low-pressure area. In the closed position, the low-pressure area, and thus the portion of the piston's actuating section located therein, offers no surface for the fluid of the pressure chamber to act upon. Therefore, the differential pressure influences the closing force.

[0023] If the low-pressure area is in air-conducting communication with the environment, the closing force can be assisted, for example with a spring or spring system, as described above. This spring or spring system must then be adequately dimensioned.

[0024] It is also conceivable that the low-pressure area is relieved on the piston rod side of the hydraulic cylinder. In this case, the chamber of the hydraulic cylinder that houses the piston rod may be equipped with a pressure regulating system that pre-tensions the hydraulic fluid in this area. This then assists (for example, a spring may be used – see above) or even causes the closing force of the piston. Furthermore, this creates a pressure relief valve that can react individually to the respective load. If, under a relatively high load on the crusher that does not yet constitute an overload situation, the pressure in the pressure chamber of the hydraulic cylinder is increased, and the hydraulic cylinder piston moves into the pressure chamber, the pressure on the rod side (the part of the hydraulic cylinder that houses the piston rod) drops.The pressure control system then regulates the pressure on the rod side. Here, the pressure control has a limited capacity to maintain the pressure. At the pressure relief valve, the pressure control ensures that the piston of the pressure relief valve remains in the closed position. Crushing operations can therefore continue under this load condition.

[0025] If an overload situation occurs, the pressure on the rod side drops sharply and the pressure control no longer maintains the pressure on the rod side.

[0026] Simultaneously, the sharp pressure increase on the bottom side of the hydraulic cylinder causes the pressure relief valve to open. This allows the pressure relief valve to adapt to different load situations.

[0027] One possible variant of the invention is such that the cylinder of the pressure relief valve has at least one outlet opening in the area of ​​the pressure chamber, which is covered in the closed position of the piston by a body area of ​​the piston adjoining the piston pressure surface and is at least partially released in the open position of the piston, and that the outlet opening is connected indirectly or directly to a tank via a line section and / or indirectly or directly to a chamber that receives a piston rod of the hydraulic cylinder via a return line.

[0028] A particularly preferred embodiment of the invention may be such that the projection of the piston pressure surface or piston pressure surfaces of the piston transversely to the positioning direction of the piston into the closing plane preferably covers at least 5% and a maximum of 80%, and particularly preferably at least 10% and a maximum of 50%, of the projection of the piston pressure surface or piston pressure surfaces of the piston transversely to the positioning direction of the piston into the closing plane, in addition to the pressure surface sections of the bridging device.

[0029] In a preferred embodiment of the invention, a maximum of 50%, preferably a maximum of 25%, of the piston pressure surface or piston pressure surfaces of the piston is located in the closing position transverse to the direction of movement of the piston in the closing plane in the area of ​​the outlet opening.

[0030] The object of the invention is also solved by a method for operating a crusher in which it is provided that when a pressure threshold is exceeded in the pressure chamber of the hydraulic cylinder the piston of the pressure relief valve is adjusted and when a relief pressure in the pressure chamber is undershot the piston is moved back to the closed position by means of a spring.

[0031] The object of the invention is further achieved by a method for operating a crusher, in which it is provided that, in the closed state of the pressure relief valve, the projection of the piston pressure surface or the piston pressure surfaces of the piston into a projection plane transverse to the direction of movement of the piston only limits a part of the pressure chamber transverse to the direction of movement of the piston, that when a pressure threshold value in the pressure chamber of the hydraulic cylinder is exceeded, the piston of the pressure relief valve is adjusted, and when a relief pressure in the pressure chamber is undershot, the piston is moved back into the closed position by means of a spring.

[0032] The invention will be explained in more detail below with reference to exemplary embodiments illustrated in the drawings. The drawings show: Figure 1: In a perspective schematic representation, a crushing unit of a rotary impact crusher with connected machine components of the crusher; Figures 2 and 3: In a schematic representation, the crushing unit according to Figure 1 with an overload release device, Figure 4: schematic representation of the overload release device and, Figure 5: schematic representation of a pressure relief valve of the overload release device.

[0033] In Figure 1 Figure 10 shows a crushing unit 10 of a rotary impact crusher. The crushing unit 10 comprises a crusher housing in which a movable crushing element 11 is rotatably mounted. Accordingly, the movable crushing element 11 is designed as a rotor. The rotor carries impact bars 12 in the region of its outer circumference.

[0034] An upper impact arm 13 is arranged inside the crusher housing. Furthermore, another crushing element 14 is also arranged in the crusher housing, which in this case forms a lower impact arm.

[0035] A crushing gap 15 is formed between the rotor (crushing element 11) and the lower impact arm (crushing element 14). When the rotor is rotating, the radially outer ends of the impact bars 12 form an outer crushing circle. This crushing circle, together with an adjacent surface of the lower impact arm, forms the crushing gap 15. The lower impact arm 14 is pivotally mounted by means of a pivot bearing 14.1. The width of the crushing gap 15 can be adjusted by the selected pivot position of the lower impact arm.

[0036] How Figure 1As can be further seen, a material feed 16 is assigned to the crushing unit 10. Material 19.1 to be crushed can be conveyed into the crushing chamber via this material feed 16. The conveying direction is in Figure 1 symbolized by an arrow. When the material 19.1 to be crushed enters the area of ​​the crushing body 11, it is ejected outwards by the impact bars 12. In doing so, this material strikes the upper impact arm 13 and the lower impact arm 14. Upon impact with an impact bar 12, with material to be crushed located in the crushing chamber, or with the two impact arms 13, 14, the material 19.1 to be crushed is broken.

[0037] For the lower impact wing 14, this is exemplified in the Figures 2 and 3 This is shown in more detail below. When the material to be broken 19.1 strikes the breaking body 14, broken material 19.2 is produced, as shown here. Figure 2shows. As soon as this crushed material 19.2 has a grain size smaller than the crushing gap 15, this crushed material 19.2 falls through the crushing gap 15. It then enters a collection area 17 below the movable crushing element 11 (rotor). How Figure 1 As shown, a conveyor system 18 is connected to the collection area 17. The crushed material 19.2 can be transported away via this conveyor system 18.

[0038] How Figure 2 As further shown, the crushing element 14 is supported against the machine structure of the crusher by means of an actuator in the form of a hydraulic cylinder 20. The support on the machine structure, for example on the machine frame of the crusher, is not detailed in the drawings. However, in Figure 1 It is evident that the hydraulic cylinder 20 is mounted in a protected manner essentially outside the crusher housing in which the rotor is housed.

[0039] As the Figures 2 and 3 As shown, the hydraulic cylinder 20 has a cylinder 25 in which a hydraulic cylinder piston 23 is adjustable. The hydraulic cylinder piston 23 carries a piston rod 22. The piston rod 22 is equipped at its end opposite the hydraulic cylinder piston 23 with a coupling piece 21, which has a bearing element. By means of this bearing element, the coupling piece 21 is connected to a bearing 14.2 of the crusher 14. Thus, the hydraulic cylinder 20 is pivotably coupled to the crusher 14. The coupling point is at a distance from the pivot bearing 14.1.

[0040] How Figure 2 As can be seen, the hydraulic cylinder piston 23 defines a pressure chamber 24 in the cylinder 25. Hydraulic fluid, in particular hydraulic oil, is filled into the pressure chamber 24. The hydraulic cylinder piston 23 is supported against this medium. This secures the piston rod 22 and the crushing element 14 in the Figure 2The predetermined breaking position was maintained as shown.

[0041] Depending on the crushing task at hand, it is necessary to adjust the operating position of the crushing gap 15 appropriately. The crusher has a control device for this purpose. Starting from the position in Figure 2 If the crushing gap 15 is to be set wider than the position shown, hydraulic fluid is released from the pressure chamber 24. This causes the hydraulic cylinder piston 23 to retract further into the cylinder 25 until the desired crushing gap 15 is set. Conversely, if a narrower crushing gap 15 is desired, additional hydraulic fluid is added to the pressure chamber 24. This causes the hydraulic cylinder piston 23 to move, thereby increasing the size of the pressure chamber 24. The piston rod 22 extends further out of the cylinder 25. This pivots the crushing element 14 clockwise, resulting in a narrowing of the crushing gap 15.

[0042] As the Figures 2 and 3As shown, an overload release device 30 is used. This can either be directly connected to the hydraulic cylinder 20 or installed separately on the machine side.

[0043] The invention can also be implemented on another rock crusher, for example on a jaw crusher, a cone crusher or a roller crusher.

[0044] In a jaw crusher, the crushing unit has a fixed jaw as the first crushing element 11 and, opposite this, a movable jaw 14. The fixed and movable jaws are aligned at an angle to each other, so that a shaft is formed between them that tapers conically towards a crushing gap 15. The movable jaw is driven, for example, by an eccentric.

[0045] The movable jaw is moved towards and away from the fixed jaw in an elliptical motion by means of the eccentric. During this stroke, the distance between the jaws also changes. The movement of the movable jaw continuously reduces the material 19.1 to be crushed along the conical shaft until it reaches a particle size that allows it to exit the shaft through the crushing gap 15. The crushed material 19.2 falls onto a crusher discharge conveyor and is conveyed further. The movable jaw can be supported against the machine frame by means of an actuator 20, which can, for example, be in the form of a hydraulic cylinder 20. The hydraulic cylinder 20 can be configured, for example, as described above. An overload release device 30 can then be coupled to the hydraulic cylinder 20.

[0046] Figure 4Figure 2 illustrates a variant embodiment of an overload release device 30. The illustration again shows the hydraulic cylinder 20 with the hydraulic cylinder piston 23 guided in the cylinder 25, which is coupled to the piston rod 22. The piston rod 22 extends from the cylinder 25. The piston rod 22 is arranged in a chamber 26 of the cylinder, which forms the rod end of the hydraulic cylinder 20. Outside the cylinder 25, the piston rod 22 is coupled to the crushing element 14 by means of a transmission device 27. In the simplest case, the transmission device 27 can be formed by the coupling piece 21.

[0047] The pressure chamber 24 of the hydraulic cylinder 20 is connected to a pressure relief valve 40 via a pressure line 31. The chamber 26 (rod side) of the hydraulic cylinder 20 is hydraulically connected to a pressure relief valve 60 via a return line 33 and a collecting line 34.

[0048] The following refers to Figure 5 A possible embodiment of a pressure relief valve 40 is explained. Preferably, the pressure relief valve 40 is installed in place of the overload release device 30, which is hydraulically connected to the pressure chamber 24 via the pressure line 31.

[0049] Figure 5 Figure 40 illustrates that the pressure relief valve has a cylinder 41. A piston 43 is guided linearly adjustable within the cylinder 41.

[0050] The cylinder 41 has an inner cylinder wall 41.1, which is preferably hollow cylindrical. The inner cylinder wall 41.1 forms a sliding surface 41.8. The piston 43 is guided in a sealed manner on the sliding surface 41.8. The piston 43 may have a cylindrical outer wall 43.1 that faces the sliding surface 41.8 and is preferably guided on it.

[0051] The cylinder 41 has one or more passages 41.3 that connect a low-pressure area 41.2 of the pressure relief valve 40 to the environment, as will be explained in more detail later. The at least one passage 41.3 can be provided, preferably in a base of a sleeve part, which is preferably designed as the cylinder base 41.4 of the cylinder 41, as Figure 5 shows.

[0052] How Figure 5 As can be further seen, the cylinder 41 has at least one outlet opening 41.5, which is preferably provided as a through-hole in the cylinder wall. Preferably, the at least one outlet opening 41.5 is arranged at a distance from the cylinder base 41.4, preferably in the area of ​​the cylinder 41 facing away from the cylinder base 41.4.

[0053] Inside the cylinder 41, a bridging device 42, for example in the form of a projection extending into the cylinder interior, in particular in the form of a mandrel, is held, as shown here. Fig. 5 The bridging device 42 is preferably fixedly connected to the cylinder 41. It is also possible that the bridging device 42 is not fixedly connected to the cylinder 41. For example, the bridging device 42 may have radial play. This allows, for example, the compensation of manufacturing tolerances. Additionally or alternatively, it is also conceivable that the bridging device 42 has axial play, for example, to serve as a storage element.

[0054] According to the present embodiment, the bridging device 42 can be coupled to the cylinder 41, preferably the cylinder base 41.4, by means of a connecting section 42.1.

[0055] The bridging device 42 has a carrier 42.2 which supports a head 42.3. The head 42.3 has a pressure surface section 42.4. In the closed state of the pressure relief valve 40, the pressure surface section 42.4 defines a pressure chamber 41.6 within the cylinder 41.

[0056] The pressure surface section 42.4 can be designed as a flat surface, as shown. Figure 5 This is shown. In particular, the pressure surface section 42.4 can be disk-shaped, especially as a circular disk. However, it is also conceivable that the pressure surface section 42.4 is composed of several surface parts that do not necessarily have to lie in a single plane, but nevertheless define the pressure chamber 41.6. In this case, it is advantageous if the projection of all surface parts of the pressure surface section 42.4 onto a plane perpendicular to the central longitudinal axis M of the cylinder 41 forms a circular disk.

[0057] Figure 5This shows that the projected area of ​​the pressure surface section 42.4 in a plane transverse to the direction of movement of the piston 43 (in particular perpendicular to the central longitudinal axis M of the cylinder 41) does not completely delimit the pressure chamber 41.6 on one side. In particular, it may be the case that Figure 5 shows that a residual surface, in particular a ring surface, is present radially outside this projected surface.

[0058] The piston 43 can preferably be designed in the form of a sleeve, as shown. It is particularly preferred that the piston 43 is rotationally symmetrical. The piston 43 can form a guide surface 43.6 with its, preferably cylindrical, inner surface. By means of the guide surface 43.6, the piston 43 can preferably be adjusted and sealed on the bridging device 42 in the direction of the central longitudinal axis M. Preferably, the piston 43 extends through the aforementioned residual surface.

[0059] The cylindrical outer surface of the piston 43 forms an outer wall 43.1, which can be guided in a sealed manner against the inner sliding surface 41.8 of the cylinder inner wall 41.1.

[0060] Facing the base, in particular the cylinder base 41.4, the piston 43 has a projection that forms a support section 43.4. The support section 43.4 has an adjusting section 43.5, which is directly or indirectly supported by a spring 44, which, as in the present case, can be designed as a coil spring. At the opposite end, the spring 44 can be directly or indirectly supported, for example, against the cylinder 41 or the aforementioned sleeve part, preferably against the base or cylinder base 41.4.

[0061] The spring 44 is preferably at least partially located in the low-pressure area 41.2. Likewise, the piston 43 with its support section 43.4 can be arranged in the low-pressure area 41.2.

[0062] In Figure 5The closed position of the pressure relief valve 40 is shown. In this state, the piston 43 rests against a valve seat 41.7 of the cylinder 41, with the piston 43 closing the at least one outlet opening 41.5. The piston 43 is biased against the valve seat 41.7 by means of the spring 44. The valve seat 41.7 is provided as a circumferential surface, preferably as an annular surface, in the region of the inner cylinder wall 41.4, as shown. Figure 5 shows.

[0063] How Figure 5 As illustrated, the piston 43 may, in the region of its end facing the pressure chamber 41.6, bear against the valve seat 41.7 with a sealing section. Preferably, the sealing section is arranged in the region of the end face of the piston 43, as shown. Figure 5 shows.

[0064] The piston 43 has a piston pressure surface 43.2 which laterally delimits the pressure chamber 41.6 in certain areas. The piston pressure surface 43.2 can preferably be designed in the form of a circumferential annular surface, as shown here.

[0065] The projections of the pressure surface section 42.4 of the bridging device 42 and the piston pressure surface 43.2 of the piston 43 into a plane transverse to the direction of movement of the piston 43, in particular perpendicular to the central longitudinal axis M, into a projection plane, delimit the pressure chamber 41.6 transversely to the direction of movement of the piston 43 on one side. The projected surfaces do not overlap. However, they may also partially overlap. The surface normals to the projected piston pressure surface 43.2 and the pressure surface section 42.4 preferably point in the same direction, in the present embodiment in the direction opposite to the piston base 41.4.

[0066] The piston 43 continues to partially limit the pressure chamber 41.6 radially on the outside with its inner wall 43.3.

[0067] The pressure relief valve 40 is connected to the pressure chamber 41.6 and the pressure line 31, thus to the pressure chamber 24 of the hydraulic cylinder 20.

[0068] The low-pressure area 41.2 is connected to the environment via at least one passage 41.3. It is possible that the ambient air pressure is present in the low-pressure area 41.2 if an air-conducting connection is created via the at least one passage 41.3.

[0069] Alternatively, the low-pressure section 41.2 is connected to the chamber 26 of the hydraulic cylinder 20 via a line section 32 and the return line 33. This means that the pressure of the rod side of the hydraulic cylinder 20 (pressure in chamber 26) is present at the low-pressure section 41.2.

[0070] During normal crushing operation and with a set crushing gap of 15, the pressure relief valve 40 is in the position shown in Figure 5 The position shown. The pressure of pressure chamber 24 is also applied to pressure chamber 41.6. If the crushing forces increase during normal crushing operation, for example, when harder rock material is being crushed, the transmission device 27 adjusts the piston rod 22 of the hydraulic cylinder 20 in the cylinder 25. This also moves the hydraulic cylinder piston 23. If a critical limit pressure is not exceeded, the crushing gap 15 widens slightly, for example, due to the compressibility of the fluid (especially the hydraulic oil) and / or an elastically limited adjustable component, without the pressure relief valve 40 being triggered. The system thus adapts without interrupting the crushing operation.

[0071] Preferably, a pressure control system is assigned to chamber 26, i.e., the rod side of the hydraulic cylinder 20, which pre-tensions the hydraulic fluid in this area. This then assists the closing force of the piston 43 caused by the spring 44 when the low-pressure area 41.2 is hydraulically connected to the rod side. Furthermore, this creates a pressure relief valve 40 that can react individually to the respective load case. If, under a relatively high load on the crusher that does not yet constitute an overload situation, the pressure in the pressure chamber 24 of the hydraulic cylinder 20 is increased, with the hydraulic cylinder piston 23 of the hydraulic cylinder 20 retracting into the pressure chamber 24, the pressure on the rod side drops. The pressure control system then adjusts the pressure on the rod side. The pressure control system has a limited capacity to maintain the pressure in this case.At the pressure relief valve 40, the pressure control thus ensures that the piston 43 of the pressure relief valve 40 remains in the closed position. The crushing operation can therefore continue under this load condition.

[0072] If an overload situation occurs, the pressure on the rod side drops sharply, and the pressure regulator can no longer maintain the pressure on that side. This pressure drop, in conjunction with the sudden increase in pressure in pressure chamber 24 and thus in pressure chamber 41.6, leads to an adjustment of the piston 43 in the direction of the central longitudinal axis M. This releases at least one outlet opening 41.5 of the pressure relief valve 40. The fluid held in pressure chamber 41.6 expands through the outlet opening 41.5. It is possible that at least one outlet opening 41.5 leads into the pipe section 32.

[0073] If the low-pressure area 41.2 is in air-conducting communication with the environment, the pressure relief valve opens when the opening force acting on the piston 43 in the direction of the central longitudinal axis M, resulting from the pressure in the pressure chamber 41.6 and the effective piston pressure area, exceeds the closing force acting in the opposite direction. The closing force results from the spring force of the spring 44 plus the pressure force, which is calculated from the ambient pressure and the boundary surface of the piston 43, projected into a plane transverse to the direction of movement of the piston 43, and which defines the low-pressure area 42.6.

[0074] The fluid flowing from the pressure relief valve 40 enters the chamber 26 of the hydraulic cylinder 20. Since the chamber 26 cannot hold all the displaced fluid, some of it is diverted to a tank 36. For this purpose, the line section 32 is connected to a pressure relief valve 60 via a manifold 34. Downstream of the pressure relief valve 60, the excess fluid is fed to the tank 36 via a drain 35. The pressure relief valve 60 is designed to open only above a certain pressure threshold to establish the connection to the tank 36. To reduce the number of parts, the design of the pressure relief valve 60 can, for example, be similar to that of the pressure relief valve 40.

[0075] After the overload condition has ended, hydraulic fluid is pumped into the pressure chamber 24 of the hydraulic cylinder 20 via a control system until the desired width of the crushing gap 15 is restored. The hydraulic fluid can be returned from the tank 36 to the pressure chamber 24 by means of a pump (not shown).

Claims

1. A crusher for mineral materials or recycling materials, in particular a rotary impact crusher, jaw crusher, cone crusher or roll crusher, having a crusher unit (10), which has a first crusher body (11), in particular a rotor or a crushing jaw, wherein the first crusher body (11) is assigned to a second movable crusher body (14), in particular an impact rocker or a crushing jaw, wherein a crushing gap (15) is formed between the crusher bodies (11, 14), wherein a hydraulic cylinder (20) is coupled to one of the crusher bodies (11, 14), which hydraulic cylinder is disposed and designed to permit a motion of the coupled crusher body (11, 14), which motion increases the width of the crushing gap (15) in an evasive motion, wherein a pressure space (24) of the hydraulic cylinder (20) is connected to a pressure chamber (41.6) of a pressure relief valve (40) of an overload triggering device (30), wherein a piston (43) of the pressure relief valve (40) can be moved between a closed position and an open position, wherein a fluid-conveying connection between the pressure chamber (41.6) and a pressure equalization area (B) is blocked in the closed position and in the open position the fluid-conveying connection is at least sectionally opened, and wherein the piston (43) has at least one piston pressure surface (43.2) by means of which the piston (43) delimits the pressure chamber (41.6) in the closed position transversely to the actuating direction of the piston (43), characterized in that in the closed state of the pressure relief valve, the projection of the piston pressure surface(s) (43.2) of the piston (43) in a projection plane transverse to the actuating direction of the piston (43), preferably in the closing plane, delimits only a part of the pressure chamber (41.6) transverse to the actuating direction of the piston (43).

2. The crusher according to claim 1, characterized in that a bridging device (42) is provided, relative to which the piston (43) can adjusted, in that the bridging device (42) has at least one pressure surface section (42.4) which delimits the pressure chamber (41.6) transversely to the actuating direction of the piston (43), and in that a projection of the pressure surface section(s) (42.4) in the direction of the actuating motion of the piston (43) in the projection plane does not or does not completely cover the piston pressure surface(s) (43.2).

3. The crusher according to claim 2, characterized in that surface normals on the projections of the piston pressure surface(s) (43.2) and the pressure surface section(s) (42.4) point in the same direction.

4. The crusher according to any of claims 1 to 3, characterized in that the piston (43) has a cylindrical outer wall (43.1) by means of which it faces an inner cylinder wall (41.1) of the cylinder (41) forming the pressure chamber (41.6), and in that the piston (43) is annular and comprises a preferably cylindrical inner wall (43.3).

5. The crusher according to any of claims 1 to 4, characterized in that a support section (43.4) of the piston (43) is supported outside the pressure chamber (41.6) with respect to a spring (44), wherein the spring (44) transfers a preload force into the piston (43) in the direction of the closed position of the piston (43) in order to preload the piston (43) against a valve seat (41.7).

6. The crusher according to any of claims 2 to 5, characterized in that the bridging device (42) is indirectly or directly connected, in particular in a stationary or movable manner, to the / one cylinder of the pressure relief valve (40) by means of a connection section (42.1), wherein preferably provision is made for the bridging device (42) to be adjustable in the direction of the actuating motion of the piston (43) and / or transversely to the actuating direction of the piston (43).

7. The crusher according to any of claims 1 to 6, characterized in that the bridging device (42) holds a head (42.3) on a beam (42.2) in the cylinder interior, and in that the head (42.3) forms or bears the at least one pressure surface section (42.4).

8. The crusher according to any of claims 1 to 7, characterized in that the piston (43) delimits a low-pressure area (41.2) of the pressure-relief valve (40) with respect to the pressure chamber (41.6), and in that the piston (43) is moved in the low-pressure area (41.2) by an actuating section (43.5) when it is moved from the closed position into the open position.

9. The crusher according to claim 8, characterized in that the low-pressure area (41.2) is connected to the environment via at least one passage (41.3) in an air-conveying connection or hydraulically to a hydraulic component, in particular to the hydraulic cylinder (20), preferably to a chamber, which accommodates a piston rod (22) of the hydraulic cylinder (20).

10. The crusher according to any of claims 1 to 9, characterized in that the cylinder (41) of the pressure relief valve (40) comprises at least one outflow opening (41.5) in the area of the pressure chamber (41.6), which outflow opening in the closed position of the piston (43) is covered by a body area of the piston (43) adjoining the piston pressure surface (43.2) and, in the open position of the piston (43), is at least partially uncovered, and in that the outflow opening (41.5) is connected via a line section (32) directly or indirectly to a tank (36) and / or directly or indirectly via a return line (33) to a chamber (26) which accommodates a piston rod (22) of the hydraulic cylinder (20).

11. The crusher according to any of claims 1 to 10, characterized in that the projection of the piston pressure surface(s) (43.2) of the piston (43) transverse to the actuating direction of the piston (43) into the / a closing plane covers at least 5%, at most 80%, particularly preferably at least 10% and at most 50% of the projection of the piston pressure surface(s) (43.2) of the piston (43) transverse to the actuating direction of the piston (43) in the closing plane plus the pressure surface sections (42.4) of the bridging device (42).

12. The crusher according to any of claims 1 to 11, characterized in that a maximum of 50%, preferably a maximum of 25%, of the projection of the piston pressure surface(s) (43.2) of the piston (43) is located transverse to the actuating direction of the piston (43) in the / a closing plane in the area of the outflow opening (41.5).

13. A method for operating a crusher for mineral materials or recycling materials, in particular a rotary impact crusher, jaw crusher, cone crusher or roll crusher, having a crusher unit (10), which has a first crusher body (11), in particular a rotor or a crushing jaw, wherein the first crusher body (11) is assigned to a second movable crusher body (14), in particular an impact rocker or a crushing jaw, wherein a crushing gap (15) is formed between the crusher bodies (11, 14), wherein a hydraulic cylinder (20) is coupled to one of the crusher bodies (11, 14), which hydraulic cylinder conducts an evasive motion in an overload operation to permit a motion of the coupled crusher body (11, 14), which motion increases the width of the crushing gap (15), wherein a pressure space (24) of the hydraulic cylinder (20) is connected to a pressure chamber (41.6) of a pressure relief valve (40) of an overload triggering device (30), wherein a piston (43) of the pressure relief valve (40) can be moved between a closed position and an open position, wherein a fluid-conveying connection between the pressure chamber (41.6) and a pressure equalization area (B) is blocked in the closed position and in the open position the fluid-conveying connection is at least sectionally opened, and wherein the piston (43) has at least one piston pressure surface (43.2) by means of which the piston (43) delimits the pressure chamber (41.6) in the closed position transverse to the actuating direction of the piston (43), characterized in that the projection of the piston pressure surface(s) (43.2) of the piston (43) in a projection plane transverse to the actuating direction of the piston delimits only a part of the pressure chamber (41.6) transverse to the actuating direction of the piston (43), in that when a pressure threshold value in the pressure space (24) of the hydraulic cylinder (20) is exceeded, the piston (43) of the pressure relief valve (40) is moved and when the pressure in the pressure chamber (41.6) falls below a relief pressure, the piston (43) is returned to the closed position by means of a spring (44).

14. A method according to claim 13, characterized in that the crusher is designed according to any of claims 1 to 12.