A telescopic forklift load limit detection valve assembly and alarm system

Abstract

The present invention discloses a load-limiting detection valve assembly and alarm system for a telescopic forklift, comprising a load-holding valve 53, the drive-end oil circuit side of the load-holding valve 53 being connected to a main safety valve 52 and a load-adjusting valve 54, a pressure sensor being connected to the load-end oil circuit side of the load-holding valve 53, and a shut-off valve 51 being installed between the drive-end oil circuit and the load-end oil circuit; the detection valve assembly being installed on a boom cylinder 1, which supports a first-stage telescopic arm 2, a second-stage telescopic arm 3 being installed at the front end of the first-stage telescopic arm 2, and a cargo fork being installed at the front end of the second-stage telescopic arm 3. This system resolves operational safety hazards existing in telescopic forklifts. The system comprises a detection valve assembly, an alarm display, and data processing. By detecting and analyzing the operating pressure of the rodless chamber of the boom cylinder, the system calculates the total amount of load that the cargo fork can lift, issues an alarm to the operator, and assists the operator in forking operations, thereby greatly improving the safety of telescopic arm aerial operations.

Description

Technical Field

[0001] The present invention relates to the field of telescopic arm forklift operations, and in particular to a load limiting device installed on a telescopic arm. Background Art

[0002] In the field of telescopic forklift operation, high altitude and heavy load operation of telescopic arms are often involved (see Figure 1 ), there are safety hazards such as overload, vehicle instability and overturning. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: to address the problem of overweight that may occur during the operation of a telescopic arm forklift, an alarm system integrating load detection, load limitation and adjustable limitation is provided.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A load limit detection valve assembly for a telescopic forklift includes a load holding valve 53. The drive-end oil circuit of the load holding valve 53 is connected to a main safety valve 52 and a load adjustment valve 54. A pressure sensor is connected to the load-end oil circuit of the load holding valve 53. A shut-off valve 51 is installed between the drive-end oil circuit and the load-end oil circuit.

[0006] The main safety valve 52 sets the maximum operating pressure of the operating oil circuit, and the load regulating valve 54 adjusts the pressure threshold according to the operating environment, and its set value does not exceed the set value of the main safety valve 52.

[0007] The pressure sensor is connected to an alarm display 6 , which is provided with a load display scale 62 , a load indicator light 63 and a buzzer 61 .

[0008] A load limit alarm system for a telescopic forklift includes the above-mentioned load limit detection valve assembly for the telescopic forklift. The detection valve assembly is installed on a luffing cylinder 1. The luffing cylinder 1 supports a first-stage telescopic arm 2. A second-stage telescopic arm 3 is installed at the front end of the first-stage telescopic arm 2. A fork is installed at the front end of the second-stage telescopic arm 3.

[0009] The cylinder barrel 13 and the piston rod 14 of the variable amplitude cylinder are sealed and combined into a rodless chamber 11 and a rod chamber 12. The oil inlet and outlet ports of the rod chamber 12 are connected to the oil inlet and outlet port seat 15 of the rodless chamber through a hard pipe 16. The oil inlet and outlet ports of the rodless chamber 11 and the rod chamber 12 are integrated into the oil inlet and outlet port seat 15, and the load holding valve 54 of the detection valve assembly cooperates with the two oil ports of the inlet and outlet port seat 15.

[0010] The alarm display instrument 6 is provided with a load display scale 62 with four partitions and four corresponding load indicator lights 63, and a buzzer 61 emits a sound prompt according to the pressure rise.

[0011] The maximum load is calculated based on the pressure threshold set by the load adjustment valve.

[0012] Beneficial effects of the present invention:

[0013] To address potential operational safety hazards associated with telescopic forklifts, the system consists of a detection valve assembly, an alarm display, and data processing. Through pressure detection and analysis of the rodless chamber of the luffing cylinder, the system calculates the total load that the fork can lift, issues an alarm to the operator, and assists them in forking operations, greatly improving the safety of telescopic arm aerial operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of telescopic arm operation.

[0015] Figure 2 It is a schematic diagram of the overall structure of the telescopic arm load limiting system.

[0016] Figure 3 yes Figure 2 Partial detail drawing.

[0017] Figure 4 This is the structural principle diagram of the variable amplitude cylinder.

[0018] Figure 5 This is the principle diagram of the detection valve assembly.

[0019] Figure 6 This is a schematic diagram of the alarm display. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0021] Example 1:

[0022] like Figure 5 This is a schematic diagram of the structure of the load limiting detection valve assembly. The detection valve assembly integrates the shut-off function, the main safety valve function, the load holding valve function and the load adjustment function, including the shut-off valve 51, the main safety valve 52, the load holding valve 53 and the load adjustment valve 54. The drive-end oil circuit side of the load holding valve 53 is connected to the main safety valve 52 and the load adjustment valve 54. The load-end oil circuit side of the load holding valve 53 is connected to a pressure sensor. The shut-off valve 51 is installed between the drive-end oil circuit and the load-end oil circuit.

[0023] The main safety valve 52 sets the maximum operating pressure of the operating oil circuit, and the load regulating valve 54 adjusts the pressure threshold according to the operating environment, and its set value does not exceed the set value of the main safety valve 52.

[0024] Function of main safety valve 52: The main safety valve sets the maximum operating pressure of the luffing cylinder operating oil circuit. The value is less than or equal to the set pressure of the vehicle hydraulic system. It determines the maximum forklift weight and is used to protect the safety of the vehicle hydraulic system and operating oil circuit.

[0025] Function of the load holding valve 53: To solve the problem of abnormal falling of the telescopic arm caused by failure or burst of other components, joints, pipelines, etc. in the hydraulic system, to keep the volume of the rodless chamber and the rod chamber of the variable-length oil cylinder unchanged, and to maintain a safe fork lifting height for the load.

[0026] Function of the load adjustment valve 54: The load adjustment valve can set the operating pressure of the variable-luffing cylinder. The maximum value can be set to the main safety valve pressure. The operating capacity can be appropriately adjusted according to the safety needs of the working environment (such as plateau sites, outdoor uneven sites, etc.). The load adjustment valve takes priority and the size of the pressure adjustment determines the weight of the safe fork-lifted load.

[0027] Function of shut-off valve 51: shuts off the oil circuit of the load holding valve. It is in the normally disconnected state during normal operation, ensuring that the load holding valve functions properly. When the operating pressure needs to be adjusted, after manual connection, the operating pressure values ​​read in real time from the Ma and I / P ports can assist in completing the load adjustment function. After the adjustment is completed, it must be manually switched to the normally disconnected state.

[0028] Example 2:

[0029] like Figure 2 The calculation model selects the load limit working condition of the telescopic arm operation. The first-level telescopic arm 2 is in a horizontal posture, the second-level telescopic arm 3 is fully extended, the fork lifts the rated load 4, the variable-length oil cylinder 1 supports all the above calculated loads, and the detection valve assembly 5 is installed on the oil inlet and outlet seats of the variable-length oil cylinder.

[0030] Calculation principle: According to the principle of moment balance, the weight of the telescopic arm is G0, the length of the arm is L2, and the weight of the load is G F , the arm length is L3, the thrust of the variable amplitude cylinder is F, the arm length is L1, and the following equilibrium relationship exists:

[0031] G0·L2+G F L3=F L1

[0032] Right now:

[0033] That is: the thrust F of the variable amplitude cylinder, the telescopic arm torque G0·L2 and the load torque G F The sum of L3 is in direct proportion.

[0034] The variable amplitude oil cylinder is mainly composed of a cylinder barrel 13 and a piston rod 14, which are sealed and combined into a rodless chamber 11 and a rod chamber 12. The rod chamber is connected to the oil inlet and outlet seat 15 of the rodless chamber through a hard tube 16, that is, the oil inlets and outlets of the rod chamber and the rodless chamber are integrated into the oil inlet and outlet seat 15, which is convenient for installing the detection valve assembly 5.

[0035] In the thrust calculation of the luffing cylinder:

[0036] Where:

[0037] F—thrust of the luffing cylinder;

[0038] D—cylinder diameter;

[0039] p—operating pressure.

[0040] Here, we use reverse calculation to set a pressure value to determine the maximum load that can be lifted. This includes the L3's closest lift and the L3's furthest lift. In essence, this turns a fixed load limit into a conveniently adjustable system that can adapt to various environments and working conditions.

[0041] When the diameter of the luffing cylinder is determined, the thrust of the luffing cylinder depends on the operating pressure, that is, the operating pressure determines the size of the load. Therefore, by limiting the operating pressure of the luffing cylinder, the load weight of the fork lift can be limited, and by adjusting the operating pressure of the luffing cylinder, the load weight of the fork lift can be adjusted.

[0042] The purpose of designing the test valve is to limit and adjust the operating pressure of the variable amplitude cylinder. The test valve assembly integrates the cut-off function, main safety valve function, load holding valve function and load adjustment function. The functional principle is as follows Figure 5 The center shut-off valve 51, main safety valve 52, load holding valve 53, and load adjustment valve 54 are installed on the inlet and outlet ports of the luffing cylinder. A' is connected to port A of the inlet and outlet port, supplying oil to the rodless chamber of the luffing cylinder. B' is connected to port B of the inlet and outlet port, supplying oil to the rod chamber of the luffing cylinder. Ma and Mb are used to measure the operating pressure of the rodless and rod chambers, respectively. The I / P pressure sensor monitors the operating pressure of the rodless chamber in real time and transmits the pressure value back to the alarm display.

[0043] Function of main safety valve 52: The main safety valve sets the maximum operating pressure of the luffing cylinder operating oil circuit. The value is less than or equal to the set pressure of the vehicle hydraulic system. It determines the maximum forklift weight and is used to protect the safety of the vehicle hydraulic system and operating oil circuit.

[0044] Function of the load holding valve 53: To solve the problem of abnormal falling of the telescopic arm caused by failure or burst of other components, joints, pipelines, etc. in the hydraulic system, to keep the volume of the rodless chamber and the rod chamber of the variable-length oil cylinder unchanged, and to maintain a safe fork lifting height for the load.

[0045] Function of the load adjustment valve 54: The load adjustment valve can set the operating pressure of the variable-luffing cylinder. The maximum value can be set to the main safety valve pressure. The operating capacity can be appropriately adjusted according to the safety needs of the working environment (such as plateau sites, outdoor uneven sites, etc.). The load adjustment valve takes priority and the size of the pressure adjustment determines the weight of the safe fork-lifted load.

[0046] Function of shut-off valve 51: shuts off the oil circuit of the load holding valve. It is in the normally disconnected state during normal operation, ensuring that the load holding valve functions properly. When the operating pressure needs to be adjusted, after manual connection, the operating pressure values ​​read in real time from the Ma and I / P ports can assist in completing the load adjustment function. After the adjustment is completed, it must be manually switched to the normally disconnected state.

[0047] Alarm display 6 (such as Figure 6 The device (shown) processes and displays the operating pressure signal, which originates from the I / P pressure sensor of the test valve assembly. The alarm display, after processing the data, provides visual and audible prompts and alarms to the operator via the load display scale 62, load indicator light 63, and buzzer 61.

[0048] The alarm display is equipped with a load display scale with four partitions (light load, medium load, heavy load and overweight load) and corresponding four load indicator lights. The load display scale lights up proportionally from low to high according to the lightness of the fork-lifted load. The light load area displays green climbing, the medium load area displays orange climbing, and the heavy load area and overweight load area display red climbing; the load indicator lights light up accordingly according to the climbing situation, the light load area flashes green, the medium load area flashes orange, the heavy load area flashes red, and the overweight load area is always red; the buzzer gives a sound prompt according to the climbing situation, the light load and medium load are silent, the heavy load gives intermittent sound, and the overweight load gives a constant sound.

[0049] The four zones set by the alarm display are automatically allocated proportionally according to the set operating pressure limit. The overload state set by the alarm display is the limit set by the load adjustment valve. If the load weight exceeds the limit, the operation is not allowed.

Claims

1. A telescopic forklift load limit detection valve assembly, comprising a load holding valve (53), characterized in that: The driving end oil circuit side of the load holding valve (53) is connected to the main safety valve (52) and the load regulating valve (54), the load end oil circuit side of the load holding valve (53) is connected to the pressure sensor, and a cut-off valve (51) is installed between the driving end oil circuit and the load end oil circuit; Function of the load holding valve (53): to solve the abnormal falling of the telescopic arm caused by failure or burst of other components, joints and pipelines in the hydraulic system, to keep the volume of the rodless chamber and the rod chamber of the variable-length oil cylinder unchanged, and to maintain the safe fork lifting height of the load; The main safety valve (52) sets the maximum operating pressure of the operating oil circuit, and the load regulating valve (54) adjusts the pressure threshold according to the operating environment, and its setting value does not exceed the setting value of the main safety valve (52); Function of the cut-off valve (51): cuts off the oil circuit of the load holding valve (53) and is in a normally disconnected state during normal operation; The pressure sensor monitors the operating pressure of the rodless cavity in real time.

2. The telescopic forklift load limit detection valve assembly according to claim 1, characterized in that: The pressure sensor is connected to an alarm display instrument (6), and the alarm display instrument is provided with a load display scale (62), a load indicator light (63) and a buzzer (61).

3. A telescopic forklift load limit alarm system, comprising the telescopic forklift load limit detection valve assembly according to claim 2, characterized in that: The detection valve assembly is installed on the luffing oil cylinder (1), the luffing oil cylinder (1) supports the first telescopic arm (2), the front end of the first telescopic arm (2) is installed with the second telescopic arm (3), and the front end of the second telescopic arm (3) is installed with a fork.

4. The telescopic forklift load limit alarm system according to claim 3, characterized in that: The cylinder barrel (13) and the piston rod (14) of the variable amplitude oil cylinder are sealed and combined to form a rodless chamber (11) and a rod chamber (12); the oil inlet and outlet ports of the rod chamber (12) are connected to the oil inlet and outlet port seat (15) of the rodless chamber through a hard pipe (16); the oil inlet and outlet ports of the rodless chamber (11) and the rod chamber (12) are integrated into the oil inlet and outlet port seat (15); and the load holding valve (54) of the detection valve assembly is matched with the two oil ports of the oil inlet and outlet port seat (15).

5. The telescopic forklift load limit alarm system according to claim 4, characterized in that: The alarm display instrument (6) is provided with a load display scale (62) with four partitions and four corresponding load indicator lights (63), and a buzzer (61) emits a sound prompt according to the pressure value climbing situation.

6. The telescopic forklift load limit alarm system according to claim 3, characterized in that: The maximum load is calculated based on the pressure threshold set by the load regulating valve (54).

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