Method for preventing collision between reclaimer's slewing mechanism and dam foundation

Abstract

The present invention relates to the technical field of reclaimers, and specifically to a method for preventing a reclaimer's slewing mechanism from colliding with a dam foundation. When the rear end of the reclaimer's slewing mechanism rotates from the left side of the dam foundation toward the collision area, the right-side induction switch is first triggered by the left-side induction plate. After receiving the induction signal from the right-side induction switch, the controller gradually reduces the reclaimer's slewing speed via a frequency converter. When the left-side induction switch is triggered by the left-side induction plate, the controller reduces the reclaimer's slewing speed to zero and applies the brake via a slewing brake. By adding an induction switch and an induction plate, and setting the control logic for the frequency converter and slewing brake linkage based on the trigger signal of the induction switch, refined control of the reclaimer's cantilever near the dam foundation is achieved, thereby achieving a better anti-collision function.

Description

Technical Field

[0001] The present invention relates to the technical field of reclaimers, and in particular to a method for preventing a reclaimer rotary mechanism from colliding with a dam foundation. Background Art

[0002] Reclaimers are typically installed on a concrete dam foundation, which is elevated above the ground level. Reclaimers require frequent reciprocating boom movements to access the underlying material. Because portions of the boom are below the dam foundation during this operation, collisions are a high risk.

[0003] The reclaimer's slewing mechanism is generally driven by a frequency converter and an asynchronous motor, with a high-speed brake installed on the motor output shaft. In traditional control methods, when the cantilever is about to collide with the dam foundation while slewing, a mechanical lever switch is triggered, after which the PLC controller disconnects the slewing command and stops the slewing action. Traditional parking control is relatively rough and rigid, and the cantilever's stop position is easily affected by the slewing inertia speed and wind force, causing the reclaimer to collide with the dam foundation or fail to retrieve materials at the edge of the stacking yard. Summary of the Invention

[0004] In response to the above problems, an embodiment of the present invention provides a method for preventing a reclaimer rotary mechanism from colliding with a dam foundation.

[0005] One aspect of the present invention provides a method for preventing a reclaimer's slewing mechanism from colliding with a dam foundation, which is applied to an anti-collision system. The anti-collision system includes: two induction switches with induction faces downwards installed on the edge of a steel structure above the tail of the reclaimer's slewing mechanism, two strip-shaped induction plates installed on the inner side of the reclaimer's slewing track corresponding to the induction switch tracks, a frequency converter, a slewing brake and a controller for driving the reclaimer to slew, wherein the two induction switches, the frequency converter and the slewing brake are all electrically connected to the controller; the two induction switches are respectively counted as a left induction switch and a right induction switch. When the axis of the reclaimer's cantilever coincides with the center line of the dam foundation, the induction switches are connected to the controller. The left induction switch and the right induction switch are symmetrical about the center line of the dam foundation, and the spacing between the left induction switch and the right induction switch on the slewing track is the length of the arc track of the induction switch sliding during the period when the reclaimer's slewing speed decreases from the maximum value to zero value due to inertia when the reclaimer is operating at the maximum allowable wind speed; the two strip-shaped induction plates are counted as the left induction plate and the right induction plate, and the left induction plate and the right induction plate are symmetrical about the center line of the dam foundation. The length of the left induction plate and the right induction plate is the spacing between the two induction switches, and the area between the minimum spacing between the two strip-shaped induction plates is the collision area where the reclaimer's slewing mechanism collides with the dam foundation; the method includes:

[0006] When the tail of the reclaimer's slewing mechanism rotates from the left side of the dam foundation toward the collision area, the right induction switch is first triggered by the left induction plate. After receiving the induction signal from the right induction switch, the controller gradually reduces the reclaimer's slewing speed through the frequency converter. When the left induction switch is triggered by the left induction plate, the controller reduces the reclaimer's slewing speed to zero and applies the slewing brake.

[0007] When the tail of the reclaimer's rotating mechanism rotates from the right side of the dam foundation toward the collision area, the left induction switch is first triggered by the right induction plate. After receiving the induction signal from the left induction switch, the controller gradually reduces the reclaimer's rotating speed through the frequency converter; when the right induction switch is triggered by the right induction plate, the controller reduces the reclaimer's rotating speed to zero and brakes it through the slewing brake.

[0008] Compared with the existing technology, the beneficial effect of the present invention is that by adding an induction switch and an induction plate, the inverter and the slewing brake linkage control logic is set based on the trigger signal of the induction switch, and the refined control and parking of the material reclaimer cantilever near the dam foundation is realized, thereby achieving better anti-collision function.

[0009] An optional, step-by-step process to reduce the reclaimer's rotation speed includes:

[0010] The reclaimer rotation speed is gradually reduced according to fixed time intervals and fixed speed reduction gradients.

[0011] Optionally, when a swing operation is required, the controller controls the frequency converter to enable excitation, and after the swing brake is controlled to open, a speed value is input to the frequency converter.

[0012] Optionally, after the controller gives the reclaimer rotation command to the frequency converter, if the frequency converter does not feedback a normal enable signal, the rotary brake is controlled to remain in the engaged state. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of this application, and do not constitute a limitation of the present invention. In the drawings:

[0014] Figure 1 A schematic structural diagram of a reclaimer provided in an embodiment of the present invention;

[0015] Figure 2 A diagram showing the arrangement of the induction switch and induction sheet when the cantilever axis coincides with the center line of the dam foundation, provided by an embodiment of the present invention;

[0016] Figure 3 A schematic diagram of a reclaimer rotary mechanism according to an embodiment of the present invention performing a rotary motion from the right side of the dam foundation toward the collision area;

[0017] Figure 4A schematic diagram of the tail portion of a reclaimer rotary mechanism rotating from the left side of the dam foundation toward the collision area provided in an embodiment of the present invention.

[0018] Among them, there are the steel structure 1 above the tail of the slewing mechanism, the slewing track 2, the reclaimer cantilever 3, the dam foundation 4, the collision area 5, the left side of the dam foundation 6, the right side of the dam foundation 7, the left induction switch 8, the right induction switch 9, the left induction plate 10, and the right induction plate 11. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0020] See also Figures 1-4 The method for preventing the reclaimer slewing mechanism from colliding with the dam foundation provided by an embodiment of the present invention is applied to an anti-collision system, which includes: two induction switches with induction faces downwards installed on the edge of the steel structure 1 above the tail of the reclaimer slewing mechanism, two strip-shaped induction plates installed on the inner side of the reclaimer slewing track 2 corresponding to the induction switch tracks, a frequency converter, a slewing brake and a controller for driving the reclaimer to rotate, wherein the two induction switches, the frequency converter and the slewing brake are all electrically connected to the controller; the two induction switches are respectively counted as the left induction switch 8 and the right induction switch 9, and when the axis of the reclaimer cantilever 3 coincides with the center line of the dam foundation 4, the left induction switch 8 and the right induction switch 9 are in contact. The induction switch 9 is symmetrical about the center line of the dam foundation 4. The distance between the left induction switch 8 and the right induction switch 9 on the rotary track 2 is the length of the arc trajectory of the induction switch sliding during the period when the reclaimer's rotation speed decreases from the maximum value to zero by inertia when the reclaimer is operating at the maximum allowable wind speed; the two strip-shaped induction plates are counted as the left induction plate 10 and the right induction plate 11, and the left induction plate 10 and the right induction plate 11 are symmetrical about the center line of the dam foundation 4. The length of the left induction plate 10 and the right induction plate 11 is the distance between the two induction switches, and the area between the minimum distance between the two strip-shaped induction plates is the collision area 5 where the reclaimer's rotary mechanism collides with the dam foundation 4; in implementation, the method includes:

[0021] When the tail of the reclaimer's slewing mechanism rotates from the left side 6 of the dam foundation toward the collision area 5, the right-side induction switch 9 is first triggered by the left-side induction plate 10. After receiving the induction signal from the right-side induction switch 9, the controller gradually reduces the reclaimer's slewing speed through the frequency converter. When the left-side induction switch 8 is triggered by the left-side induction plate 10, the controller reduces the reclaimer's slewing speed to zero and applies the slewing brake.

[0022] When the tail of the reclaimer's rotating mechanism rotates from the right side 7 of the dam foundation toward the collision area 5, the left induction switch 8 is first triggered by the right induction plate 11. After receiving the induction signal from the left induction switch 8, the controller gradually reduces the reclaimer's rotating speed through the frequency converter; when the right induction switch 9 is triggered by the right induction plate 11, the controller reduces the reclaimer's rotating speed to zero and brakes it through the slewing brake.

[0023] During implementation, the aforementioned controller automatically reduces the rotation speed until the rotation stops in the interval. The area where the reclaimer cantilever 3 swings can be called the "near dam foundation interval". In this interval, the induction plate continuously triggers the corresponding induction switch and allows a certain amount of eccentricity in the rotating track. To ensure the accuracy of the signal, the induction switch will not be triggered except in the interval near the dam foundation. In specific implementation, two sections of 80# channel steel of equal length connected together can be used as induction plates to cover the sliding tracks of the induction switches on the left and right sides, and allow the rotating track to have a horizontal eccentricity of less than 50mm.

[0024] The process of gradually reducing the reclaimer's rotation speed includes gradually reducing the reclaimer's rotation speed according to a fixed time interval and a fixed speed reduction gradient. For example, starting from the time the left or right sensor switch is triggered, the controller automatically limits the rotation speed to no more than 80% of the rated speed in the first 1-2 seconds, based on the current rotation speed as the rated speed. In the third and fourth seconds, the controller limits the rotation speed to no more than 50% of the rated speed. After the fourth second, the controller limits the rotation speed to no more than 20% of the rated speed until the right or left sensor switch is triggered, at which point the rotation speed is reset to 0. During implementation, no speed limit is imposed on the rotation speed in the direction away from the dam foundation.

[0025] During implementation, the inverter continuous excitation enable function can also be set. Specifically, when a rotation operation is required, the controller controls the inverter to enable excitation. When the control rotation brake is opened, the speed value is input to the inverter; when the controller rotation command is disconnected, the inverter continues to maintain the excitation enable state for 4 seconds, during which the speed is set to 0.

[0026] After the controller gives the reclaimer rotation command to the inverter, if the inverter does not feedback a normal enable signal, the rotary brake is controlled to remain in the engaged state.

[0027] The solution provided by the embodiment of the present invention, by adding an induction switch and an induction plate, sets the linkage control logic of the frequency converter and the slewing brake based on the trigger signal of the induction switch, thereby realizing fine control and parking of the cantilever of the material reclaimer near the dam foundation, thereby achieving better anti-collision function.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A method for preventing a reclaimer's rotary mechanism from colliding with a dam foundation, characterized in that: Applied to the anti-collision system, the anti-collision system includes: two induction switches with induction faces downwards installed on the edge of the steel structure above the tail of the reclaimer's rotating mechanism, two strip-shaped induction plates installed on the inner side of the reclaimer's rotating track corresponding to the induction switch tracks, a frequency converter, a slewing brake and a controller for driving the reclaimer to rotate, wherein the two induction switches, the frequency converter and the slewing brake are all electrically connected to the controller; the two induction switches are respectively counted as the left induction switch and the right induction switch. When the cantilever axis of the reclaimer coincides with the center line of the dam foundation, the left induction switch and the right induction switch are based on the dam foundation. The left and right sensor switches are symmetrical about the center line of the dam foundation, and the distance between the left and right sensor switches on the rotary track is the length of the arc track of the sensor switch sliding during the period when the reclaimer's rotation speed decreases from the maximum value to zero by inertia when the reclaimer is operating at the maximum allowable wind speed; the two strip-shaped sensor plates are counted as the left and right sensor plates, and the left and right sensor plates are symmetrical about the center line of the dam foundation. The length of the left and right sensor plates is the distance between the two sensor switches, and the area between the minimum distance between the two strip-shaped sensor plates is the collision area where the reclaimer's rotary mechanism collides with the dam foundation; the method includes: When the tail of the reclaimer's slewing mechanism rotates from the left side of the dam foundation toward the collision area, the right induction switch is first triggered by the left induction plate. After receiving the induction signal from the right induction switch, the controller gradually reduces the reclaimer's slewing speed through the frequency converter. When the left induction switch is triggered by the left induction plate, the controller reduces the reclaimer's slewing speed to zero and applies the slewing brake. When the tail of the reclaimer's rotating mechanism rotates from the right side of the dam foundation toward the collision area, the left induction switch is first triggered by the right induction plate. After receiving the induction signal from the left induction switch, the controller gradually reduces the reclaimer's rotating speed through the frequency converter; when the right induction switch is triggered by the right induction plate, the controller reduces the reclaimer's rotating speed to zero and brakes it through the slewing brake.

2. The method for preventing the reclaimer's rotating mechanism from colliding with the dam foundation according to claim 1, characterized in that: The process of gradually reducing the reclaimer rotation speed includes: The reclaimer rotation speed is gradually reduced according to fixed time intervals and fixed speed reduction gradients.

3. The method for preventing the reclaimer's rotating mechanism from colliding with the dam foundation according to claim 1, characterized in that: When a swing operation is required, the controller controls the frequency converter to enable excitation, and after the swing brake is controlled to open, the speed value is input to the frequency converter.

4. The method for preventing the reclaimer's rotating mechanism from colliding with the dam foundation according to claim 1, characterized in that: After the controller gives the reclaimer rotation command to the inverter, if the inverter does not feedback a normal enable signal, the rotary brake is controlled to remain in the engaged state.

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