Method for controlling a dual braking system of a travelling crane

Abstract

The application discloses a control method of a double braking system of a travelling crane, comprising a travelling crane and a travelling crane track beam; travelling crane track grooves are formed on both sides of the travelling crane track beam; the travelling crane is provided with a pair of rollers at the upper end; the method further comprises a motor for driving the rollers; the rollers comprise inflatable tires and a brake air pump; a displacement sensor is arranged on the body of the travelling crane; a rotation speed sensor and a torque sensor are arranged on the axle of the driving roller; the rotation speed monitored by the rotation speed sensor is W; the outer diameter of the roller is d under normal conditions; the torque monitored by the torque sensor is N; a torque threshold value is N1; the relative speed of the travelling crane and the travelling crane track beam monitored by the displacement sensor is V; and the braking intensity of the travelling crane is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of overhead cranes. Background Technology

[0002] Existing overhead cranes generally employ a single motor braking system, relying solely on motor reverse drag for deceleration and stopping. However, in actual operating conditions, the loads carried by these cranes are often substantial. When overloaded loads or excessive speed occur, the motor's power is insufficient to effectively suppress the vehicle's kinetic energy, leading to risks such as wheel slippage, insufficient braking force, or even brake failure. Furthermore, existing technologies struggle to monitor key data such as crane speed and wheel rotation speed in real time during incidents. They lack precise perception of the wheel-rail motion during braking and fail to correlate data such as vehicle speed, wheel speed, and motor torque. This results in the crane being unable to take timely and appropriate countermeasures when malfunctions occur, leading to poor braking stability, excessive braking distances, and ultimately, a high risk of serious safety accidents. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the shortcomings of the prior art, the present invention provides a control method for a dual braking system of a gantry crane, which effectively improves the braking strength of the gantry crane.

[0004] Technical solution: To achieve the above objective, the present invention provides a control method for a dual braking system of a traveling crane, comprising a traveling crane and a traveling crane track beam; both sides of the traveling crane track beam are formed with traveling track grooves, and the upper end of the traveling crane has a pair of rollers that roll and engage in the traveling track grooves, and also includes a motor for driving the rollers.

[0005] The roller includes an inflatable outer tire and a brake air pump; under normal conditions, the outer diameter of the inflatable outer tire of the roller is smaller than the longitudinal width of the track groove.

[0006] The gantry crane is equipped with displacement sensors that can monitor the relative speed between the gantry crane and the gantry crane track beam. The drive rollers are equipped with speed sensors and torque sensors on their axles.

[0007] The rotational speed monitored by the speed sensor is W. Under normal conditions, the outer diameter of the roller is d. The torque monitored by the torque sensor is N. Let a torque threshold be N1. The relative speed between the gantry crane and the gantry crane track beam monitored by the displacement sensor is V.

[0008] The gantry crane moves linearly along the gantry crane track beam under the drive of the motor. When the gantry crane needs to stop, the motor is controlled to apply reverse torque, so that the moving gantry crane gradually stops.

[0009] When either of the conditions V > πdW or N > N1 is satisfied, control the braking air pump to further inflate the inflatable outer tire, so that the outer diameter of the inflatable outer tire of the roller expands to the longitudinal width of the running track groove, causing the tire body to expand and tightly fit and press against the upper and lower walls of the running track groove.

[0010] Furthermore, the mass of the crane body is M1, the mass of the goods is M2, and the total mass M of the crane is M = M1 + M2; a mass threshold is set as M0, and a speed threshold is set as V0. When the controller receives a braking instruction, at the initial stage when the motor applies a reverse torque, if V = πdW and N < N1, and M < M0 and V < V0 are satisfied, the braking air pump does not intervene; when either of the conditions M > M0 or V > V0 is satisfied, even if V = πdW and N < N1 at this time, the braking air pump immediately intervenes.

[0011] Furthermore, the displacement sensor calculates and indirectly obtains the relative speed V between the crane and the crane track beam by monitoring the relative displacement between the crane and the crane track beam according to the formula V = (S2 - S1) / Δt.

[0012] Furthermore, a transmission is provided on the crane, and the motor drives the connecting wheel shaft through the transmission.

[0013] Furthermore, a pressure sensor is provided inside the inflatable outer tire. The pressure sensor can monitor the internal pressure of the inflatable outer tire. Under normal conditions, the pressure monitored by the pressure sensor is P. After the braking air pump further inflates the inflatable outer tire, the pressure monitored by the pressure sensor is P1.

[0014] Furthermore, the crane track beam includes a web. The roller includes a first roller and a second roller. One sides of the first roller and the second roller close to the web are respectively connected to a first anti-deviation shaft and a second anti-deviation shaft from the axis. Under normal conditions, the ends of the first anti-deviation shaft and the second anti-deviation shaft close to each other both maintain a gap with the web or the ends of the first anti-deviation shaft and the second anti-deviation shaft close to each other are in rolling fit with the side wall of the web through universal ball bearings.

[0015] Furthermore, the crane further includes a crane frame. The crane frame is fixedly connected to a horizontal hanging rod through a connecting body. The two ends of the hanging rod are respectively fixedly connected with an upward-extending first roller support and a second roller support through a first adjustable connecting member and a second adjustable connecting member. The first wheel shaft of the first roller and the second wheel shaft of the second roller are respectively rotatably installed on the first roller support and the second roller support through bearings. <​Beneficial effects: The control method of the dual braking system of the overhead crane of the present invention, based on motor braking, further inflates the outer tire by means of a brake air pump. The outer diameter of the inflatable outer tire expands to the longitudinal width of the track groove, so that the tire body is tightly attached to the upper and lower walls of the overhead crane track groove, increasing the maximum static friction between the tire body and the upper and lower walls of the overhead crane track groove. The linear velocity of the tire body and the upper wall is opposite to that of the tire body and the lower wall. Under the constraint of static friction, they remain stationary. Furthermore, the brake air pump needs to intervene at a reasonable time interval to ensure the safety of the overhead crane operation, realize the dual braking of the overhead crane, improve the braking strength of the overhead crane, and reduce the braking hysteresis effect caused by the inflation delay of the inflatable outer tire. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overhead crane body structure for the invention.

[0018] Figure 2 This is a schematic diagram of the overhead crane track beam structure for the invention.

[0019] Figure 3 This is a schematic diagram of the overall structure of the overhead crane for the invention. Detailed Implementation

[0020] The invention will now be further described with reference to the accompanying drawings.

[0021] As attached Figures 1 to 3 The control method of the dual braking system of the overhead crane shown includes an overhead crane 1 and an overhead crane track beam 2; both sides of the overhead crane track beam 2 are formed with concave track grooves 14 that extend in the length direction; the overhead crane 1 has a pair of rollers 9 at its upper end, the rollers 9 are rolled in the track grooves 14; and a motor 8 is also included to drive the rollers 9.

[0022] The roller 9 includes an inflatable outer tire 10 and a brake air pump; under normal conditions, the outer diameter of the inflatable outer tire 10 of the roller 9 is smaller than the longitudinal width of the track groove 14, there is a gap between the upper end of the roller 9 and the upper wall 16, and the lower end of the roller 9 rolls with the lower wall 15.

[0023] The gantry crane 1 is equipped with a displacement sensor on its body, which can monitor the relative speed between the gantry crane 1 and the gantry crane track beam 2. The drive roller 9 is equipped with a speed sensor and a torque sensor on its axle. The displacement sensor is a laser rangefinder. A reflector is installed at a fixed position at the end of the gantry crane track beam 2. The laser rangefinder emits a laser pulse that hits the reflector. The distance between the gantry crane 1 and the end of the gantry crane track beam 2 is obtained by calculating the round-trip time of the laser. A mass sensor is also installed to monitor the mass of the cargo.

[0024] The rotational speed monitored by the speed sensor is W. Under normal conditions, the outer diameter of the roller 9 is d. The torque monitored by the torque sensor is N. Let a torque threshold be N1. The relative speed between the gantry crane 1 and the gantry crane track beam 2 monitored by the displacement sensor is V.

[0025] The calculation is performed based on the data monitored by the sensors. The roller speed W monitored by the speed sensor is used to calculate the linear velocity V1 of the roller according to the formula V1=πdW. The relative velocity V between the crane 1 and the crane track beam 2 is calculated according to the formula V=(S2-S1) / Δt based on the displacement S monitored by the displacement sensor.

[0026] The gantry crane 1 moves linearly along the gantry crane track beam 2 under the drive of the motor 8. When the gantry crane 1 needs to stop, the power supply in the direction of motor rotation is disconnected and the power supply in the opposite direction is supplied to the motor. The motor 8 is controlled to apply reverse torque, and the motor generates electromagnetic torque opposite to the direction of rotation, thereby causing the traveling gantry crane 1 to gradually stop.

[0027] When either V>πdW or N>N1 is met; V>πdW means the relative speed between the gantry crane 1 and the gantry crane track beam 2 is greater than the linear speed of the roller 9, indicating that the roller 9 is slipping; N>N1 means the torque exceeds the threshold, indicating that normal torque cannot stop the cargo, resulting in cargo overload. The brake air pump is then used to further inflate the inflatable tire 10, expanding its outer diameter to the longitudinal width of the gantry track groove 14. This causes the tire to expand and tightly press against the upper and lower walls of the gantry track groove, increasing the maximum static friction between the tire and the upper and lower walls of the gantry track groove 14. The linear speed of the tire and the upper wall 16 is opposite to that of the tire and the lower wall 15, achieving dual braking through the motor 8 and the inflatable tire 10. However, inflating the inflatable tire 10 takes time. If the sensor detects a fault, further inflating the tire will be delayed, which could easily lead to a safety accident.

[0028] However, if the brake pump intervenes too early, the inflatable tire 10 will be used frequently, and the tire material is prone to fatigue accumulation, which can lead to rubber aging, tire cracking, and other problems. At the same time, when the brake pump inflates the inflatable tire 10, the moment the tire expands and tightly presses against the upper and lower walls of the overhead crane track 14, it can easily cause the overhead crane 1 to fluctuate up and down, causing the loaded cargo to shake and be damaged. If the brake pump intervenes too late, the overhead crane will have already experienced safety malfunctions such as slippage or rollback, which will not only damage the overhead crane and track, but also endanger personnel safety. Therefore, the brake pump needs to intervene within a reasonable time range. Based on this, the method is improved.

[0029] The mass of the body of the gantry crane 1 is M1, the mass of the goods is M2, and the total mass M of the gantry crane 1 is M = M1 + M2. Let a mass threshold be M0 and a speed threshold be V0. When the controller receives a braking instruction, in the initial stage when the motor 8 applies a reverse torque, if under the premise that V = πdW and N < N1, and when M < M0 and V < V0, it means that the gantry crane is operating normally and without failure. The total mass of the gantry crane 1 and the relative speed between the gantry crane 1 and the gantry crane track beam 2 are both within the safety thresholds, and only the motor 8 is relied on for braking, and the braking air pump does not intervene. When either the condition M > M0 or V > V0 is satisfied, it means that the gantry crane 1 is extremely likely to be in danger. Even if at this time V = πdW and N < N1, the braking air pump immediately intervenes. When V > V0, it means that the operating speed of the gantry crane 1 exceeds the safety threshold. Relying only on the motor 8 for braking, the braking distance is too long and the braking intensity is low, and it is extremely easy to rush out of the gantry crane track beam 14. When M > M0, it means that the mass of the gantry crane 1 exceeds the safety threshold, and the gantry crane 1 is overweight. If only relying on the motor 8 for braking, the inertia of the goods is too large, and the electric braking cannot provide sufficient braking force, and the gantry crane 1 is prone to risks such as slipping and brake failure. When both conditions are satisfied simultaneously, the risks of the gantry crane 1 slipping, running away, and brake failure rise sharply, and danger almost occurs. Therefore, based on the above situation, even when the gantry crane is operating normally and no failure is detected, the braking air pump needs to intervene immediately.

[0030] A pneumatic sensor is provided inside the inflatable outer tire 10. The pneumatic sensor can monitor the internal air pressure of the inflatable outer tire 10. Under normal conditions, the air pressure monitored by the pneumatic sensor is P. After the braking air pump further inflates the inflatable outer tire 10, the air pressure monitored by the pneumatic sensor is P1.

[0031] A transmission 7 is provided on the gantry crane 1. The motor 8 drives the connecting wheel shaft through the transmission 7.

[0032] The gantry crane track beam 2 includes a web 13. The roller 9 includes a first roller 9a and a second roller 9b. One sides of the first roller 9a and the second roller 9b close to the web 13 are respectively connected to a first anti-deviation shaft 11a and a second anti-deviation shaft 11b from the axis. Under normal conditions, the ends of the first anti-deviation shaft 11a and the second anti-deviation shaft 11b close to each other both maintain a gap with the web 13 or the ends of the first anti-deviation shaft 11a and the second anti-deviation shaft 11b close to each other are in rolling fit with the side wall of the web 13 through universal ball bearings, which can limit the left and right deviation of the roller 9 and play an anti-deviation guiding role. Accommodation cavities are provided inside the first anti-deviation shaft 11a and the second anti-deviation shaft 11b. The braking air pump is installed and fixed inside the first anti-deviation shaft 11a and the second anti-deviation shaft 11b. The air pressure output end of the braking air pump is communicated with the inflatable outer tire 10. The braking air pump further inflates the inflatable outer tire 10 of the roller 9. The braking air pump continuously compresses the outside air to generate highly compressed air and sends it into the inflatable outer tire 10 through a pipeline.

[0033] The gantry crane 1 further includes a gantry frame 12, which is fixedly connected to the transverse hanging rod 3 through a connecting body 17. Both ends of the hanging rod 3 are fixedly connected with upwardly extending first roller brackets 5a and second roller brackets 5b through a first adjustable connecting member 4a and a second adjustable connecting member 4b respectively. The first wheel shaft 6a of the first roller 9a and the second wheel shaft 6b of the second roller 9b are rotatably installed on the first roller bracket 5a and the second roller bracket 5b through bearings respectively.

[0034] Working principle: The rollers 9 of this gantry crane 1 rollingly cooperate with the traveling track groove 14 of the gantry crane track beam 2, and an inflatable outer tire 10 is provided for walking and rolling. Under normal conditions, the inflatable outer tire 10 is in a normal state of being properly inflated and the tire body is full and plump. The outer diameter of the inflatable outer tire 10 is smaller than the longitudinal width of the track groove. The rollers can execute commands such as moving forward, moving backward, and stopping to keep the gantry crane 1 moving normally. When moving forward, the motor 8 makes the rollers move forward by rotating at a constant speed in the forward direction. When moving backward, the rollers move backward by the motor rotating at a constant speed in the reverse direction. During the stopping process, the positive current input to the motor 8 is cut off and switched to the input of the reverse current. By using the torque generated by the reverse current, finally the rollers stop rolling. When the speed of the gantry crane 1 is fast, the braking distance of the motor 8 is long. When the goods on the gantry crane 1 are heavy, the braking strength is low. Therefore, the intervention of the inflatable outer tire for braking is required. The braking strength of the inflatable outer tire 10 is high, but it takes time for the braking air pump to inflate the inflatable outer tire 10. When the intervention timing of the braking air pump is too early, the inflatable outer tire 10 will be frequently used, and the material of the outer tire is prone to fatigue accumulation, which will further cause problems such as rubber aging and tire cracking. At the same time, when the braking air pump inflates the inflatable outer tire 10, when the tire body expands and tightly fits and presses against the upper and lower walls of the traveling track groove instantaneously, it is easy to cause the up and down fluctuations of the operation of the gantry crane 1, resulting in the shaking of the carried goods and damage; when the intervention timing of the braking air pump is too late, safety failures such as slipping and running away of the gantry crane 1 have already occurred, which will not only cause damage to the gantry crane 1 and the track, but also endanger the safety of the operators. Therefore, the braking air pump needs to intervene within a reasonable timing range.

[0035] When the gantry crane 1 needs to stop, the motor 8 is controlled to apply a reverse torque, so that the traveling gantry crane 1 gradually stops; during the process of the motor 8 applying the reverse torque, when either of the conditions V>πdW or N>N1 is satisfied, the braking air pump is controlled to further inflate the inflatable outer tire 10, so that the outer diameter of the inflatable outer tire 10 of the roller 9 expands to the longitudinal width of the traveling track groove 14, and the tire body expands and tightly fits and presses against the upper and lower walls of the traveling track groove. When the controller receives the braking instruction, at the initial stage of the motor 8 applying the reverse torque, if under the premise of V=πdW and N<N1, when M<M0 and V<V0 are satisfied, the braking air pump does not intervene; when either of the conditions M>M0 or V>V0 is satisfied, even if at this time V=πdW and N<N1, the braking air pump immediately intervenes.

[0036] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A control method for a dual braking system of an overhead crane, characterized in that: It includes a gantry crane (1) and a gantry crane track beam (2); on both sides of the gantry crane track beam (2), a traveling track groove (14) is formed. At the upper end of the gantry crane (1), there is a pair of rollers (9), and the rollers (9) are in rolling fit in the traveling track groove (14). It also includes a motor (8) for driving the rollers (9). The rollers (9) include an inflatable outer tire (10) and a braking air pump; under normal conditions, the outer diameter of the inflatable outer tire (10) of the rollers (9) is smaller than the longitudinal width of the traveling track groove (14). A displacement sensor is provided on the vehicle body of the gantry crane (1). The displacement sensor can monitor the relative speed between the gantry crane (1) and the gantry crane track beam (2). A rotational speed sensor and a torque sensor are provided on the axle of the driving rollers (9). The rotational speed monitored by the rotational speed sensor is W. Under normal conditions, the outer diameter of the rollers (9) is d, and the torque monitored by the torque sensor is N. Let a torque threshold be N1, and the relative speed between the gantry crane (1) and the gantry crane track beam (2) monitored by the displacement sensor is V. The gantry crane (1) moves linearly along the gantry crane track beam (2) under the drive of the motor (8). When the gantry crane (1) needs to stop, the motor (8) is controlled to apply a reverse torque, so that the moving gantry crane (1) gradually stops. During the process of the motor (8) applying a reverse torque, when either of the conditions V > πdW or N > N1 is satisfied, the braking air pump is controlled to further inflate the inflatable outer tire (10), so that the outer diameter of the inflatable outer tire (10) of the rollers (9) expands to the longitudinal width of the traveling track groove (14), and the tire body expands and tightly fits and presses against the upper and lower walls of the traveling track groove.

2. The control method for the dual braking system of the overhead crane according to claim 1, characterized in that: The mass of the vehicle body of the gantry crane (1) is M1, and the mass of the goods is M2. The total mass M of the gantry crane (1) is M = M1 + M + 2. Let a mass threshold be M0 and a speed threshold be V0. When the controller receives a braking instruction, at the initial stage of the motor (8) applying a reverse torque, if under the premise of V = πdW and N < N1, when M < M0 and V < V0, the braking air pump does not intervene; when either of the conditions M > M0 or V > V0 is satisfied, even if at this time V = πdW and N < N1, the braking air pump immediately intervenes.

3. The control method for the dual braking system of the overhead crane according to claim 1, characterized in that: The displacement sensor indirectly obtains the relative speed V between the gantry crane (1) and the gantry crane track beam (2) by monitoring the relative displacement between the gantry crane ( / ) and the gantry crane track beam (2) and calculating according to the formula V = (S2 - S1) / Δt.

4. The control method for the dual braking system of the overhead crane according to claim 1, characterized in that: A transmission (7) is provided on the gantry crane (1), and the motor (8) is drivingly connected to the axle through the transmission (7).

5. The control method for the dual braking system of the overhead crane according to claim 1, characterized in that: An air pressure sensor is provided inside the inflatable outer tire (10). The air pressure sensor can monitor the internal air pressure of the inflatable outer tire (10). Under normal conditions, the air pressure monitored by the air pressure sensor is P, and after the braking air pump further inflates the inflatable outer tire (10), the air pressure monitored by the air pressure sensor is P1.

6. The control method for the dual braking system of the overhead crane according to claim 1, characterized in that: The overhead crane track beam (2) includes a web (13), and the rollers (9) include a first roller (9a) and a second roller (9b). The first roller (9a) and the second roller (9b) are respectively connected from the axis to the first anti-deviation shaft (11a) and the second anti-deviation shaft (11b) on the side of the first roller (9a) and the second roller (9b) that are close to each other. Under normal conditions, the ends of the first anti-deviation shaft (11a) and the second anti-deviation shaft (11b) that are close to each other maintain a gap with the web (13), or the ends of the first anti-deviation shaft (11a) and the second anti-deviation shaft (11b) that are close to each other roll with the side wall of the web (13) through universal ball bearings.

7. The control method for the dual braking system of the overhead crane according to claim 1, characterized in that: The overhead crane (1) also includes a crane frame (12), which is fixedly connected to the horizontal hanging rod (3) via a connector (17). The two ends of the hanging rod (3) are fixedly connected to an upwardly extending first roller bracket (5a) and second roller bracket (5b) via a first adjustable connector (4a) and a second adjustable connector (4b), respectively. The first wheel axle (6a) of the first roller (9a) and the second wheel axle (6b) of the second roller (9b) are rotatably mounted on the first roller bracket (5a) and the second roller bracket (5b) via bearings.

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