Mechanism for preventing automatic outward extension of suspension arm of crane

Abstract

The utility model discloses a crane jib automatic extension prevention mechanism and belongs to the technical field of cranes. The device is characterized by comprising a multi-way valve, a balance valve, an oil cylinder, a stroke valve and a baffle, two working ports A and B of the multi-way valve are respectively connected with an outward extending oil port A1 and a contraction oil inlet B1 of the balance valve, an outward extending oil port A2 of the balance valve is connected with a rodless cavity of the oil cylinder, and a contraction oil outlet B2 of the balance valve is connected with a rod cavity of the oil cylinder; the baffle is located on a suspension arm bracket of a crane base and used for triggering the stroke valve. The stroke valve is installed on a basic arm of the suspension arm, an oil inlet of the stroke valve is connected to a pipeline between an outward extending oil port A2 of the balance valve and a rodless cavity of the oil cylinder, and an oil outlet of the stroke valve is connected to a pipeline between an outward extending oil port A1 of the balance valve and a working port A of the multi-way valve, so that an unloading oil way is formed. When the truck is folded, the travel valve on the suspension arm is matched with the baffle on the suspension arm bracket, the travel valve is triggered, automatic unloading can be achieved, and safety and convenience are achieved.

Description

Technical Field

[0001] The utility model relates to a crane boom automatic extension prevention mechanism, belonging to the technical field of cranes. Background Art

[0002] When a truck crane's boom is retracted, high-pressure oil enters the rod chamber of the hydraulic cylinder. Operators are accustomed to continuing to pump oil into the rod chamber for 2-3 seconds after the boom is fully retracted to confirm that the boom is properly retracted. Furthermore, micro-leakage in the hydraulic cylinder can easily allow high-pressure oil to enter the rodless chamber. These two phenomena can cause high pressure in the rodless chamber of the hydraulic cylinder and cause the boom to automatically extend after retraction.

[0003] The Chinese utility model patent "A crane boom with a locking function" with authorization announcement number CN216303118U fixes the end arm of the boom's telescopic arm by connecting a wire rope to the side of the boom's basic arm. However, this solution fails to solve the above-mentioned high-pressure problem of the rodless chamber of the cylinder. The boom still has the risk of extending outward, posing a safety hazard. In addition, this solution uses many accessories and is complicated to operate. This solution uses the boom structure to tighten the cylinder, and the wire rope lock will damage the boom structure. Utility Model Content

[0004] The purpose of the utility model is to address the deficiencies of the above-mentioned prior art and to provide a crane anti-boom automatic extension mechanism, which can completely solve the problem of high pressure in the rodless chamber of the cylinder and eliminate the risk of the cylinder extending after the boom is retracted.

[0005] The technical solution of the utility model is as follows:

[0006] A crane anti-jib automatic extension mechanism, characterized by comprising a multi-way valve, a balancing valve, an oil cylinder, a stroke valve, and a baffle; the oil inlet P of the multi-way valve is connected to the oil tank via a pump, the oil return port T is connected to the oil tank, the two working ports A and B of the multi-way valve are respectively connected to the extension oil inlet A1 and the retraction oil inlet B1 of the balancing valve; the extension oil port A2 of the balancing valve is connected to the rodless chamber of the oil cylinder, and the retraction oil outlet B2 of the balancing valve is connected to the rod chamber of the oil cylinder;

[0007] The baffle is located on the boom bracket of the crane base and is used to trigger the travel valve; the travel valve is installed on the basic wall of the boom, its oil inlet is connected to the pipeline between the oil port A2 extending from the balancing valve and the rodless chamber of the cylinder, and its oil outlet is connected to the pipeline between the oil inlet A1 extending from the balancing valve and the working port A of the multi-way valve, forming an unloading oil circuit.

[0008] In the above solution, an unloading oil circuit is added, and unloading is achieved through a mechanical stroke valve, which fundamentally solves the problem that the rodless chamber cannot be unloaded due to the high closing pressure of the balance valve; when retracting the vehicle, the mechanical stroke valve on the boom cooperates with the baffle on the boom bracket to trigger the stroke valve, thereby achieving automatic unloading without excessive operation, which is safe and convenient.

[0009] Furthermore, an explosion-proof valve is provided on the unloading oil line, which is connected to the oil inlet pipeline of the stroke valve. The addition of the explosion-proof valve prevents the mechanical stroke valve locking function from failing or the unloading oil line from being damaged, thereby improving safety.

[0010] Furthermore, a throttle hole is provided on the unloading oil line, and the throttle hole is provided on the pipeline between the explosion-proof valve and the stroke valve, thereby increasing throttling damping, preventing the explosion-proof valve from closing due to excessive oil unloading, and improving reliability.

[0011] Furthermore, the baffle is Z-shaped, consisting of two horizontal sections, one high and one low, and an inclined section. The lower section is screwed to the center of the boom bracket, while the higher section contacts the trigger end of the travel valve. Connecting to the crane via a single Z-shaped structural member offers a simple structure and ease of operation without compromising crane performance.

[0012] Furthermore, the baffle is provided with reinforcing ribs between the lower horizontal portion and the inclined portion to enhance the strength of the Z-shaped structure.

[0013] Furthermore, the boom bracket includes a base, which is fixedly mounted on the crane foundation; two vertical plates, symmetrically mounted on the base, support the boom; and a baffle, mounted on the base and located between the two vertical plates. The two vertical plates are used to support the stowed boom. When the boom is stowed, the central rib of the base triggers the travel valve on the boom, resolving the high-pressure issue in the rodless chamber of the oil cylinder.

[0014] Furthermore, the stroke valve is a linear stroke valve.

[0015] The utility model completely solves the problem of high pressure in the rodless chamber of the oil cylinder after the boom is retracted. Only one baffle is connected to the boom structure, and it will not affect the structural strength and crane performance. The utility model automatically prevents the boom from extending when the vehicle is retracted, and does not require unnecessary operations. It is convenient and safe, low-cost, safe and reliable, and saves a lot of after-sales costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the hydraulic oil circuit of the automatic boom extension prevention mechanism of the utility model crane;

[0017] Figure 2 This is a schematic diagram of the structure of the automatic boom extension prevention mechanism for a crane according to the present invention;

[0018] Figure 3 for Figure 2 A partial enlarged view of

[0019] Figure 4 for Figure 2 A partial enlarged view of

[0020] Figure 5 This is a schematic diagram of the installation of the middle baffle and the boom bracket of the utility model;

[0021] Figure 6 for Figure 5 A top view of

[0022] Figure 7 This is a schematic structural diagram of the baffle in the utility model;

[0023] In the figure: pump 1, multi-way valve 2, multi-way valve working port A 2-1, multi-way valve working port B 2-2, balancing valve 3, oil cylinder 4, rodless chamber 4-1, rod chamber 4-2, stroke valve 5, baffle 6, reinforcement rib 6-1, crane base 7, boom bracket 8, base 8-1, riser 8-2, oil tank 9, explosion-proof valve 10, throttle hole 11, boom 12. DETAILED DESCRIPTION

[0024] A crane anti-jib automatic extension mechanism adds an unloading oil circuit to the crane hydraulic system, comprising: a pump 1, a multi-way valve 2, a balance valve 3, an oil cylinder 4, a travel valve 5, and a baffle 6.

[0025] The multi-way valve's oil inlet P is connected to the oil tank 9 via a pump, while its oil return port T is also connected to the oil tank 9. Its two working ports, A and B, are connected to the balancing valve's extended oil inlet A1 and retracted oil inlet B1, respectively. The balancing valve's extended oil port A2 is connected to the cylinder's rodless chamber 4-1, while the balancing valve's retracted oil outlet B2 is connected to the cylinder's rod chamber 4-2. The stroke valve's oil inlet is connected to the pipeline between the balancing valve's extended oil port A2 and the cylinder's rodless chamber, while its oil outlet is connected to the pipeline between the balancing valve's extended oil inlet A1 and the multi-way valve's working port A, forming a load-releasing oil circuit.

[0026] like Figure 2 、 Figure 3 、 Figure 4 As shown, the baffle 6 is mounted on the boom bracket 8 of the crane base 7 and is used to trigger the travel valve; the travel valve is mounted on the boom basic arm.

[0027] In one embodiment of the present invention, an explosion-proof valve 10 is further provided on the unloading oil circuit, and the explosion-proof valve is connected to the oil inlet pipeline of the travel valve.

[0028] In one embodiment of the present invention, a throttle hole 11 is further provided on the unloading oil circuit, and the throttle hole is provided on the pipeline between the explosion-proof valve and the stroke valve.

[0029] In one embodiment of the present invention, Figure 5 、 Figure 6 、 Figure 7As shown, the baffle is Z-shaped, consisting of two horizontal sections, one high and one low, and an inclined section. The lower horizontal section is screwed to the center of the boom bracket, while the higher horizontal section contacts the trigger end of the travel valve. A reinforcing rib 6-1 is provided between the lower horizontal section and the inclined section.

[0030] In one embodiment of the present invention, Figure 5 、 Figure 6 As shown, the boom bracket 8 includes a base 8-1 and two vertical plates 8-2. The base is fixedly mounted on the crane base; the two vertical plates are symmetrically mounted on the base to support the boom; the baffle is mounted on the base and is located between the two vertical plates.

[0031] like Figure 1 As shown in the figure, the hydraulic oil circuit of the crane's anti-boom automatic extension mechanism is as follows:

[0032] 1. The oil outlet of pump 1 is connected to the oil inlet P of multi-way valve 2, and the oil return port T of multi-way valve 2 is connected to the oil tank 9;

[0033] 2. The two working ports A and B of the multi-way valve 2 are connected to the extending oil inlet A1 and the retracting oil inlet B1 of the balancing valve 3 respectively. The extending oil port A2 and the retracting oil outlet B2 of the balancing valve are connected to the rodless chamber 4-1 and the rod chamber 4-2 of the oil cylinder respectively.

[0034] 3. Connect the second oil circuit, the unloading oil circuit, between the multi-way valve working port A and the external oil inlet port A1 of the balancing valve. The oil circuit starts at point C4 and connects to the mechanical stroke valve 5, the throttle orifice 11, the explosion-proof valve 10, and finally to the pipeline between the external oil port A2 of the balancing valve and the rodless chamber of the cylinder.

[0035] 4. When the mechanical stroke valve is opened (in contact with the baffle), the hydraulic oil in the rodless chamber of the cylinder can directly pass through the unloading oil circuit and the multi-way valve (the middle position function is Y-type) and return directly to the oil tank, thereby realizing the unloading of the rodless chamber of the cylinder.

[0036] When the crane is powered on and the boom is raised, the mechanical stroke valve 5 disengages from the baffle 6 (fixed to the crane base 7), and the stroke valve spool closes. At this point, the multi-way valve is operated, causing oil to flow out of its working port A. Hydraulic oil then flows through the counterbalance valve's extension oil inlet A1 and extension oil port A2, entering the rodless chamber of the cylinder, extending the cylinder and, in turn, extending the boom. When the multi-way valve's working port B flows out, hydraulic oil flows through the counterbalance valve's retraction oil inlet B1 and retraction oil port B2, entering the rod chamber of the cylinder, retracting the cylinder and, in turn, retracting the boom.

[0037] During normal operation, in order to prevent the mechanical stroke valve locking function from failing or the unloading oil line from being damaged, an explosion-proof valve is added to achieve emergency locking.

[0038] At the end of the operation, the crane is fully retracted, the boom is lowered, and the mechanical stroke valve opening switch (trigger end) falls on the baffle (the baffle is fixed to the crane base), opening the stroke valve spool. At this time, the rodless chamber of the cylinder is directly connected to the oil tank through the explosion-proof valve, throttle orifice, mechanical stroke valve, and the Y-shaped functional spool of the multi-way valve. This oil circuit directs the hydraulic oil in the rodless chamber to the oil tank. To prevent excessive flow from closing the explosion-proof valve, a throttle orifice is added to the oil circuit to ensure that the unloading oil circuit is always unobstructed. The hydraulic oil in the rod chamber is directly directed to the oil tank through the unloading oil circuit, solving the problem of internal leakage and external extension of the cylinder, and thus solving the problem of external extension of the boom.

Claims

1. A crane anti-jib automatic extension mechanism, characterized in that: It includes a multi-way valve, a balancing valve, an oil cylinder, a stroke valve, and a baffle; the two working ports A and B of the multi-way valve are respectively connected to the extending oil inlet A1 and the retracting oil inlet B1 of the balancing valve, the extending oil port A2 of the balancing valve is connected to the rodless chamber of the oil cylinder, and the retracting oil outlet B2 of the balancing valve is connected to the rod chamber of the oil cylinder; The baffle is located on the boom bracket of the crane base and is used to trigger the travel valve; the travel valve is installed on the boom, and its oil inlet is connected to the pipeline between the external oil port A2 of the balancing valve and the rodless chamber of the cylinder, and its oil outlet is connected to the pipeline between the external oil inlet A1 of the balancing valve and the working port A of the multi-way valve to form an unloading oil circuit.

2. A crane anti-jib automatic extension mechanism according to claim 1, characterized in that: The unloading oil line is also provided with an explosion-proof valve, which is connected to the oil inlet pipeline of the travel valve.

3. The crane boom automatic extension prevention mechanism according to claim 2, characterized in that: The unloading oil line is also provided with a throttle hole, and the throttle hole is provided on the pipeline between the explosion-proof valve and the stroke valve.

4. A crane boom automatic extension prevention mechanism according to claim 3, characterized in that: The baffle is Z-shaped and consists of two horizontal parts, one high and one low, and an inclined part. The lower horizontal part is installed at the middle position of the boom bracket by screws, and the higher horizontal part is used to contact the trigger end of the travel valve.

5. The crane boom automatic extension prevention mechanism according to claim 4 is characterized in that: The baffle is provided with reinforcing ribs between the lower horizontal portion and the inclined portion.

6. The crane boom automatic extension prevention mechanism according to claim 4, characterized in that: The boom bracket includes a base and two vertical plates. The base is fixedly installed on the crane base; the two vertical plates are symmetrically installed on the base to support the boom; the baffle is installed on the base and is located between the two vertical plates.

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