Free telescopic force limiter system based on single length sensor

Abstract

A free telescopic force limiter system based on a single length sensor belongs to the technical field of cranes, and adopts a length angle sensor to detect the total length of all arms, an action detector is mounted on a basic arm body and used for detecting whether an extending arm body moves, and a force limiter receives signals of the length angle sensor and the action detector and sends the signals to the crane. And the extension length is calculated according to a length algorithm of a first-extension arm body or according to a length algorithm that a second-stage telescopic oil cylinder drives other arm bodies to move. The device is simple in system and higher in reliability, effectively ensures that an input signal for converting the arm length is consistent with an actual action, and does not calculate wrong data due to the failure and unpredictable problems of an executing mechanism for the operational data of the actual arm length and the physical data state of the cargo boom by the force limiter.

Description

Technical Field

[0001] The utility model relates to a free telescopic force limiter system based on a single length sensor, belonging to the technical field of cranes. Background Art

[0002] For cranes with dual-cylinder telescopic booms, such as those on truck cranes and truck cranes, the primary telescopic cylinder drives the movement of the first boom, while the secondary telescopic cylinder drives the movement of the second, third, fourth (or more) booms. The crane's boom length is a key factor in determining the crane's load capacity. However, the force limiter safety protection system for dual-cylinder telescopic booms uses different length calculations for single booms and two (or more) booms. There are two main methods for calculating the length of dual-cylinder telescopic booms in the prior art:

[0003] 1. Two length and angle sensors are used to measure the telescopic length of a boom driven by the primary telescopic cylinder and the telescopic length of two, three, four (or more) booms driven by the secondary telescopic cylinder. These values ​​are fed into the force limiter to calculate the load. However, this approach suffers from structural complexity, low reliability, and high cost. Furthermore, if either of the two length and angle sensors fails, the force limiter algorithm will fail. Furthermore, due to the tight space constraints of this approach, the cables of the length and angle sensors are prone to unraveling or snapping.

[0004] 2. Use a length and angle sensor. When the operator presses the switch, the signal is transmitted to the force limiter to identify whether the first-stage telescopic cylinder or the second-stage telescopic cylinder is in action. Then the force limiter uses the corresponding length algorithm to calculate the actual arm length and the load weight. For example: the application publication number is: CN117533967A, and the invention name is: A single-length measurement arbitrary telescopic control method and system for a double-cylinder rope crane. This patent uses the operating signal of the second-stage cylinder switching to provide a calculation basis for the force limiter. However, the technical solution of this patent requires that the system input signal must be consistent with the actual action. It is only credible when the control valve group and the motion mechanism are executed completely according to the operator's will. It does not have the ability to distinguish the actual state of the actual actuator, and is prone to incorrect calculation of the force limiter data.

[0005] In the second method, if the operator presses the toggle switch, the force limiter starts to execute the algorithm in the switched order. However, there may be problems such as the switch signal not being transmitted to the control valve, or the control valve failing to switch, or oil leakage in the actuator. In this case, the extension and retraction of the boom cannot be performed as desired at the corresponding level, so the force limiter will calculate data that does not conform to the actual state, which will cause the safety system to fail.

[0006] Therefore, it is necessary to provide a free telescopic force limiter system based on a single length sensor. When the operator switches the button to the secondary telescopic cylinder, even if the secondary telescopic cylinder fails and does not move, but the primary telescopic cylinder is moving, it can ensure that there will be no errors in the operation. Utility Model Content

[0007] The purpose of this utility model is to address the deficiencies of the above-mentioned prior art and to provide a free telescopic force limiter system based on a single length sensor. This force limiter system does not rely on the operator's will. Even if the crane arm's telescopic action is chaotic, it can ensure that the force limiter calculation data is consistent with the actual working conditions.

[0008] The technical solution of the utility model is as follows:

[0009] A free-extension force limiter system based on a single length sensor uses a length-angle sensor to detect the total length of all arms. A motion detector is installed on the basic arm body to detect whether an extended arm body is moving. The force limiter receives signals from the length-angle sensor and the motion detector, and chooses to calculate the extended length according to the length algorithm of the extended arm body, or according to the length algorithm of the secondary telescopic cylinder driving the movement of other arms.

[0010] In the above scheme, because the first telescopic cylinder and a boom are articulated, the first telescopic cylinder drives the boom in synchronous motion. A motion detector detects whether the boom is moving and transmits the signal to the force limiter for identification. A single length and angle sensor detects the total length of all arms. The force limiter, based on the actual motion of the first or second telescopic cylinder, sends a signal to the force limiter. Using a corresponding length algorithm, it calculates the actual telescopic length of the first boom and the extension length of subsequent booms, thereby calculating the actual lifting load condition.

[0011] Furthermore, the motion detector can use an infrared sensor to monitor the movement of an extension arm (the primary telescopic cylinder). Mounted on the inner wall of the primary arm, the infrared sensor senses movement of the end surface of the extension arm (the sensing distance can be adjusted as needed) and transmits the signal to the force limiter. An infrared sensor can also be used to detect the movement of the other arm (the secondary telescopic cylinder).

[0012] If the infrared sensor cannot sense the inner end surface of an extension arm, that is, the distance between the inner end surface of an extension arm and the infrared sensor exceeds the set sensing distance, it is considered that the first-level telescopic cylinder is moving, and a signal that an extension arm is moving can be sent to the force limiter, and the length algorithm of the extension arm will be executed (regardless of which arm movement is selected by the operator); if the infrared sensor senses the inner end surface of an extension arm, the extension arm is not moving, and the force limiter converts the length according to the movement algorithm of other arms driven by the second-level cylinder.

[0013] Furthermore, the motion detector can use an encoder roller, which is installed outside the basic arm body through a support plate and presses against the outer wall of an extension arm body to detect the movement of an extension arm body and transmit the signal to the force limiter.

[0014] An encoder roller is set on the basic arm body, and the trigger area of ​​the encoder roller is pressed against an extension arm body. As long as an extension arm body moves, the encoder roller can send a signal to the force limiter that the extension arm body is moving, and then the length algorithm of the extension arm body will be executed (no matter which arm movement is selected by the operator). If an extension arm body does not move, the force limiter will convert the length according to the movement algorithm of other arms driven by the secondary cylinder.

[0015] Furthermore, the motion detector can also adopt an innovative sensing mechanism, including: a micro DC generator, a roller, a light source, and a voltage sensor; the roller is connected to the input shaft of the micro DC generator and is pressed against the outer wall of an extension arm; the micro DC generator is installed outside the basic arm body through a support base, and the output end of the micro DC generator, the light source, and the switch are connected in series to form a loop, and the voltage sensor is used to detect the voltage changes at both ends of the light source and transmit the signal to the force limiter.

[0016] If one arm moves, it drives the rollers to rotate, causing the input shaft of the micro-DC generator to rotate, generating an electromotive force. This illuminates the light source in the circuit. A voltage sensor monitors the voltage across the light source to determine whether the primary telescopic cylinder is moving. If the voltage sensor detects a voltage, the force limiter executes the length calculation based on the length of the first arm. If the light source is not illuminated, the force limiter converts the length based on the movement of the other arms driven by the secondary cylinder.

[0017] Furthermore, the support seat in the above-mentioned innovative sensing mechanism includes: a Z-shaped seat body, a pair of support springs, a pair of guide rods, and a pair of guide tubes; the Z-shaped seat body is fixed to the outside of the basic arm body, and a pair of guide tubes are vertically installed on the Z-shaped seat body; a pair of guide rods are jointly installed at the bottom of the micro DC generator and are respectively placed in a pair of guide tubes; the two ends of a pair of support springs are respectively connected to the bottom of the micro DC generator and the Z-shaped seat body, and are respectively sleeved on the outside of the pair of guide tubes.

[0018] A pair of guide tubes are fixed to the Z-shaped base, and a pair of guide rods pass through them (with clearance between them to ensure smooth up and down sliding). One end of the guide rod is connected to the bottom of the micro-DC generator, and the other end is equipped with a stopper to prevent it from sliding out of the guide tube. When the arm moves, the roller, coordinated by the support spring, guide rod, and guide tube, always presses against the outer wall of the arm, ensuring smooth follow-up of the roller and power generation of the micro-DC generator.

[0019] The system of the utility model is simple and has higher reliability, and effectively ensures that the input signal of the arm length conversion is consistent with the actual action. The force limiter will not calculate the wrong data for the actual arm length and the physical data status of the crane arm due to failure of the actuator or unforeseen problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of the free-extensible force limiter system based on a single length sensor in Example 1;

[0021] Figure 2 Schematic diagram of the structure of the free-extensible force limiter system based on a single length sensor in Example 2;

[0022] Figure 3 Schematic diagram of the structure of the free-extensible force limiter system based on a single length sensor in Example 3;

[0023] Figure 4 for Figure 3 Middle partial enlarged view;

[0024] Figure 5 for Figure 3 Schematic diagram of the connection between the middle roller and the micro DC generator;

[0025] Figure 6 This is a schematic structural diagram of the support base in Example 3;

[0026] In the figure: basic arm body 1, first-stage telescopic cylinder 2, first extension arm body 3, infrared sensor 4, encoder roller 5, micro DC generator 6, roller 7, Z-shaped seat body 8, support spring 9, guide rod 10, guide tube 11. DETAILED DESCRIPTION

[0027] Example 1

[0028] A free telescopic force limiter system based on a single length sensor uses only one length and angle sensor to detect the total length of all arms. A motion detector detects whether an arm is moving and transmits the signal to the force limiter as a judgment signal of the actual movement of the first or second telescopic cylinder. The force limiter uses the corresponding length algorithm to calculate the actual telescopic length of the first arm and the extension length of the subsequent arms, thereby calculating the actual lifting working condition.

[0029] Motion detectors can use infrared sensors, such as Figure 1 As shown, an infrared sensor 4 is installed on the inner wall of the basic arm body 1 to sense the inner end surface of an extension arm body to detect whether an extension arm body 3 (first-level telescopic cylinder 2) is moving, which serves as a judgment signal of the actual movement of the first-level or second-level telescopic cylinder and transmits the signal to the force limiter.

[0030] Example 2

[0031] The difference from Example 1 is that the motion detector uses an encoder wheel, such as Figure 2 As shown, the basic arm body 1 is provided with a support plate, and an encoder roller 5 is provided on the support plate. The encoder roller presses against the outer wall of an extension arm body to detect the movement of an extension arm body, which serves as a judgment signal of the actual movement of the first or second stage telescopic cylinder and transmits the signal to the force limiter.

[0032] Example 3

[0033] Different from the first embodiment, the motion detector adopts an innovative sensing mechanism. Figure 3 、 Figure 4 、 Figure 5 As shown, the motion detector includes: a micro DC generator 6, a roller 7, a light source, and a voltage sensor. The micro DC generator 6 is installed outside the basic arm body 1 through a support base. The roller 7 is connected to the input shaft of the micro DC generator and is pressed against the outer wall of an extension arm body 3. The output end of the micro DC generator, the light source, and the switch are connected in series to form a loop. The voltage sensor is used to detect the voltage change at both ends of the light source and transmit the signal to the force limiter as a judgment signal of the actual movement of the first or second telescopic cylinder.

[0034] like Figure 6 As shown, the support base includes a Z-shaped base body 8, a pair of support springs 9, a pair of guide rods 10, and a pair of guide tubes 11. The Z-shaped base body is fixed to the outside of the basic arm body, and the pair of guide tubes are vertically fixed to the Z-shaped base body. The pair of guide rods are jointly installed at the bottom of the micro-DC generator and pass through the pair of guide tubes, with the guide rods and guide tubes slidingly fitting. The ends of the pair of support springs are respectively connected to the bottom of the micro-DC generator and the Z-shaped base body, and are respectively mounted outside the pair of guide tubes to ensure smooth follow-up of the roller and power generation of the micro-DC generator.

Claims

1. A free-extension force limiter system based on a single length sensor, characterized in that: include: A length angle sensor to detect the total length of all arms; A motion detector is installed on the basic arm body and is used to detect whether an extended arm body is moving; The force limiter receives signals from the length and angle sensor and the motion detector, and chooses to calculate the extension length according to the length algorithm of one extension arm, or according to the length algorithm of the subsequent extension arms driven by the secondary telescopic cylinder.

2. The free-extensible force limiter system based on a single length sensor according to claim 1, characterized in that: The motion detector is an infrared sensor, which is installed on the inner wall of the basic arm body and is used to sense the movement of the end surface of the extension arm body and transmit the signal to the force limiter.

3. The free-extensible force limiter system based on a single length sensor according to claim 1, characterized in that: The motion detector is an encoder roller, which is installed outside the basic arm body through a support plate and presses against the outer side wall of an extension arm body to detect the movement of the extension arm body and transmit the signal to the force limiter.

4. The free-extension force limiter system based on a single length sensor according to claim 1, characterized in that: The motion detector includes: a micro DC generator, a roller, a light source, and a voltage sensor; the roller is connected to the input shaft of the micro DC generator and presses against the outer wall of an extension arm; The micro DC generator is installed outside the basic arm body through a support base. The output end of the micro DC generator, the light source, and the switch are connected in series. The voltage sensor is used to detect the voltage change at both ends of the light source and transmit the signal to the force limiter.

5. The free-extension force limiter system based on a single length sensor according to claim 4 is characterized in that the support seat include: A Z-shaped seat body, a pair of support springs, a pair of guide rods, and a pair of guide tubes; The Z-shaped seat is fixed to the outside of the basic arm body, and a pair of guide tubes are vertically installed on the Z-shaped seat; a pair of guide rods are jointly installed at the bottom of the micro DC generator and are respectively placed in the pair of guide tubes; the two ends of a pair of support springs are respectively connected to the bottom of the micro DC generator and the Z-shaped seat, and are respectively sleeved on the outside of the pair of guide tubes.

Images