Lifting arm, truck crane

Abstract

The present invention relates to a crane, and is intended to solve the problem that the boom fixing process of the existing automobile boom is relatively cumbersome; a boom and an automobile crane are provided, wherein the boom comprises a multi-section boom, and the boom comprises a basic boom and a telescopic boom which is sleeved in sequence, and each section of the boom is provided with a limiting hole, and when all the telescopic arms are in an unextended state, the limiting holes on each section of the boom are coaxially aligned; a latch device is installed on the basic arm, and the latch device comprises a latch which can be inserted and pulled out of the limiting hole and a driving device for pushing and pulling the latch into and out of the limiting hole. In the present invention, after the telescopic arm is retracted, the limiting holes on all the booms are coaxially aligned, and the latch is inserted therein to fix the booms together, so as to prevent the telescopic arm from moving outward under the action of inertia when the boom moves with the crane, thereby avoiding safety accidents. The telescopic arm is fixed by the latch, and the operation is simple and convenient.

Description

Technical Field

[0001] The present invention relates to a crane, and more particularly to a lifting arm and a truck crane. Background Art

[0002] Most of the boom telescopic systems of truck cranes below several hundred tons are realized by telescopic cylinders and ropes. In the industry, medium-tonnage five-section boom truck cranes generally use double hydraulic cylinders and wire ropes to realize the telescopic movement of the five-section boom. The I telescopic cylinder is fixed on the basic boom, and the II telescopic cylinder is fixed on the second boom. The telescopic movement of the second boom relative to the basic boom is controlled by the I telescopic cylinder, and the telescopic movement of the third, fourth, and fifth booms relative to the second boom is controlled by the II telescopic cylinders and wire ropes.

[0003] The telescopic cylinder is connected to the telescopic arm. The telescopic cylinder pushes the telescopic arm to extend and retract. A balance valve is set on the telescopic cylinder. When the telescopic arm is extended, the hydraulic oil enters the large chamber of the cylinder through the one-way valve in the balance valve, and the piston rod of the telescopic cylinder extends, driving the telescopic arm to extend. When the piston rod of the telescopic cylinder stops extending, the one-way valve in the balance valve is closed to prevent the oil in the telescopic cylinder from returning and causing the piston rod of the telescopic cylinder to retract, playing a pressure-maintaining function. When the telescopic arm needs to be retracted, it is necessary to fill the small chamber of the telescopic cylinder with pressure oil. The pressure oil enters the small chamber of the telescopic cylinder from the retracting arm working oil port. At the same time, the pressure oil pushes the balance valve to open the one-way valve in the balance valve, allowing the oil in the large chamber of the telescopic cylinder to return, so that the rear lever piston rod of the telescopic cylinder can be retracted under the action of the pressure oil in the small chamber. When the telescopic cylinder stops retracting, the pressure oil in the retracting arm working oil port needs to be returned, the pressure in the small chamber of the telescopic cylinder is released, the one-way valve in the balance valve is closed, and the balance valve continues to maintain the pressure of the large chamber of the telescopic cylinder. If the retracting arm working oil port does not return oil, the balance valve will not be able to return to its position, that is, the oil cylinder and the boom cannot be protected by pressure. In summary, because the small chamber oil of the telescopic cylinder is returned oil, when the vehicle stops, the telescopic arm pulls the piston rod of the telescopic cylinder outward under the action of inertia. Since the small chamber of the telescopic cylinder directly returns oil through the retracting arm working oil port, there is no non-return function, causing the piston rod of the telescopic cylinder to extend, thereby causing the telescopic arm to extend and be unable to return to its original position, resulting in a telescopic arm outward failure phenomenon.

[0004] From the operation characteristics of the crane, it can be seen that when the vehicle is not in operation and driving on the road, the hook is required to be fixed to the head of the boom with a wire rope and fixed to the frame or the front of the vehicle. When the vehicle brakes while driving, the telescopic arm is composed of multiple arms, and the inertia of the telescopic arm will drive the telescopic cylinder to extend outward. The telescopic arm is fixed by the wire rope and the hook to prevent the telescopic arm from extending outward under the action of inertia. However, since the fixing process of the telescopic arm and the hook is relatively cumbersome, when the truck crane is transferred a short distance, the operator usually does not fix the hook, which causes the boom to extend outward due to inertia and cause the telescopic arm to run outward. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the boom fixing process of the existing automobile crane boom is relatively complicated, and a boom and automobile crane are provided to simplify the boom fixing process, facilitate operators to fix the boom and reduce safety accidents.

[0006] The technical solution of the present invention to achieve its purpose is as follows: provide a lifting arm, including a multi-section lifting arm, the lifting arm includes a basic arm and a telescopic arm that is sleeved in sequence, characterized in that each section of the lifting arm is provided with a limiting hole, and the limiting holes on each section of the lifting arm are coaxially aligned when all the telescopic arms are in an unextended state; a latch device is installed on the basic arm, and the latch device includes a latch that can be inserted and pulled out of the limiting hole and a driving device for pushing and pulling the latch into and out of the limiting hole. In the present invention, after the lifting arm is retracted, the limiting holes on all the lifting arms are coaxially aligned, and the latch is inserted therein to fix the lifting arms together, so as to prevent the telescopic arm from moving outward under the action of inertia when the lifting arm moves with the machine, thereby avoiding safety accidents. The telescopic arm is pinned to the basic arm by the latch, and the operation is simple and convenient.

[0007] In the lifting arm of the present invention, the latch pin and the limiting hole are clearance-matched, and the clearance is small, thereby reducing the movement between the lifting arms.

[0008] In the lifting arm of the present invention, the driving device includes a driving actuator for driving the movement of the latch and a control system for controlling the driving actuator. The latch device includes a mounting seat that is cylindrical and has an end fixed on the basic arm. The latch and the driving actuator are installed in the mounting seat.

[0009] In the crane arm of the present invention, the driving actuator is an electric motor, and the control system is a control circuit for controlling the forward and reverse rotation of the electric motor. Alternatively, the driving actuator is a hydraulic cylinder, and the control system is a hydraulic control oil circuit for controlling the extension and retraction of the hydraulic cylinder.

[0010] In the crane arm of the present invention, the hydraulic control oil circuit includes a telescopic switching control valve, a two-way hydraulic lock connected between the telescopic switching control valve and the hydraulic oil cylinder, a hydraulic pump to the telescopic switching control valve, and a hydraulic oil tank connected to the hydraulic pump. The telescopic switching control valve is a three-position four-way solenoid valve, or a mechanical valve operated by a handle.

[0011] In the lifting arm of the present invention, the hydraulic control oil circuit also includes a master control solenoid valve, the oil inlet end of the master control solenoid valve is connected to the hydraulic pump, the first oil outlet end is connected to the oil inlet end of the telescopic switching control valve, and the second oil outlet end is used to connect to the pilot control oil circuit; when the master control solenoid valve is in the left position, the oil inlet end is connected to the first oil outlet end and the second oil outlet end at the same time, and when the master control solenoid valve is in the right position, the oil inlet end is connected to the first oil outlet end, and the second oil outlet end is cut off. When the master control solenoid valve works in the left position, the plugging and pulling out of the latch can be performed, and the boarding action can also be performed. When the master control solenoid valve works in the right position, only the plugging and pulling out of the latch can be performed, and the boarding action is prohibited due to the cut-off of the pilot control oil circuit, thereby realizing the boarding lock.

[0012] In the crane arm of the present invention, the latch device also includes a latch position marking device, which includes an extended position detection switch and a retracted position detection switch linked to the latch position, and each of the extended position detection switch and the retracted position detection switch is connected to a position indicator light. The position of the oil cylinder is indicated by the indication of the position indicator light, so that the operator can easily know whether the boom is locked.

[0013] In the lifting arm of the present invention, the retracted position detection switch is linked to the master control solenoid valve, that is, when the latch is retracted to the retracted position detection switch is triggered, the master control solenoid valve works in the left position; when the latch is not retracted to the position and the retracted position detection switch is not triggered, the master control solenoid valve works in the left position.

[0014] The technical solution of the present invention to achieve its purpose is as follows: a truck crane is provided, characterized in that it includes the above-mentioned lifting arm.

[0015] Compared with the prior art, in the present invention, the latch can fix the booms together after the booms are retracted to prevent the booms from moving outwards, thereby avoiding safety accidents. The operation of pinning the booms is simple and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the truck crane in the present invention.

[0017] Figure 2 It is a structural schematic diagram of the crane arm in the present invention when the telescopic arm is extended.

[0018] Figure 3 It is a structural schematic diagram of the crane arm in the present invention when the telescopic arm is retracted.

[0019] Figure 4 It is a connection principle diagram of the hydraulic oil cylinder and the hydraulic control oil circuit of the crane arm in the present invention.

[0020] Figure 5 It is the electrical principle diagram of the latch device control in the present invention.

[0021] Figure 6 It is a structural diagram of the boom of the present invention in a state where the boom is pinned.

[0022] Figure 7 It is a structural diagram of the boom of the present invention when the boom is in a state of being released from locking.

[0023] Parts names and serial numbers in the figure:

[0024] Lifting arm 1, basic arm 11, telescopic arm 12, limiting hole 13, latch device 2, mounting seat 21, latch 22, induction unit 221, hydraulic cylinder 23, extended position detection switch 24, retracted position detection switch 25, hydraulic oil tank 31, hydraulic pump 32, telescopic switching control valve 33, two-way hydraulic lock 34, master control solenoid valve 35, relief valve 36, pilot oil circuit 37 DETAILED DESCRIPTION

[0025] The specific implementation scheme is described below with reference to the accompanying drawings.

[0026] like Figure 1 As shown, a crane arm 1 is installed on the truck crane. Figure 2 Figure 3 As shown, the crane arm 1 is composed of multiple boom sections, one of which is a basic boom 11, and the other booms are telescopic arms 12 which are sequentially sleeved in the basic arm. The telescopic arms 12 are driven to extend and retract by telescopic cylinders and ropes.

[0027] like Figure 2 Figure 3 As shown, each boom section is provided with a limiting hole 13, and a latch device 2 is installed on the basic arm 11. When each telescopic arm 12 is in an unextended state, the limiting holes 13 on each boom section are coaxially aligned.

[0028] The latch device 2 includes a latch 22 that can be inserted and removed from the limiting hole 13, a driving device for pushing and pulling the latch 22 to be inserted and removed from the limiting hole, and a mounting seat 21. The driving device includes a driving actuator for driving the latch 22 to move and a control system for controlling the driving actuator. The mounting seat 21 is cylindrical, and its end is fixed on the basic arm 11. The latch 22 and the driving actuator are installed in the mounting seat. After the latch is inserted into the limiting hole, there is a clearance fit between the latch and the limiting hole.

[0029] In this embodiment, the driving actuator is a hydraulic cylinder 23, and the control system is a hydraulic control oil circuit for controlling the extension and retraction of the hydraulic cylinder 23. In practical applications, the driving actuator may also be an electric motor, and the control system is a control circuit for controlling the forward and reverse rotation of the electric motor, and the forward and reverse rotation of the electric motor pushes the latch to move relative to the basic arm for extension and retraction.

[0030] like Figure 4As shown, the hydraulic control oil circuit includes a telescopic switching control valve 33 , a two-way hydraulic lock 34 , a hydraulic pump 32 , a hydraulic oil tank 31 , a master control solenoid valve 35 , and a relief valve 36 .

[0031] The telescopic switching control valve 33 is a three-position four-way solenoid valve, and the two-way hydraulic lock 34 is connected between the telescopic switching control valve 33 and the hydraulic cylinder 23. The two-way hydraulic lock 34 is composed of two hydraulically controlled one-way valves, which ensures that the hydraulic cylinder 23 can only be telescoped under the push of hydraulic oil. Applying external force on the piston rod of the hydraulic cylinder cannot cause the hydraulic cylinder to be telescoped.

[0032] The oil inlet of the master control solenoid valve 35 is connected to the hydraulic pump 32, the first oil outlet is connected to the oil inlet of the telescopic switching control valve 33, and the second oil outlet is used to connect to the pilot control oil circuit 37, that is, to the pilot control oil circuit of the crane's vehicle-mounting hydraulic system; when the master control solenoid valve is in the right position, its oil inlet is connected to the first oil outlet, and the second oil outlet is cut off. When the master control solenoid valve works in the left position, the plug-in and pull-out operations of the latch can be performed, and the vehicle-mounting operation can also be performed. When the master control solenoid valve works in the right position, only the plug-in and pull-out operations of the latch can be performed, and the vehicle-mounting action is prohibited due to the cutoff of the pilot control oil circuit, thereby realizing the vehicle-mounting locking.

[0033] like Figure 2 As shown, the latch device 2 also includes a latch position marking device, which includes an extended position detection switch 24 and a retracted position detection switch 25 linked to the latch position, and each of the extended position detection switch 24 and the retracted position detection switch 25 is connected to a position indicator light. The extended position detection switch 24 and the retracted position detection switch 25 are installed on the mounting seat 21 and arranged at intervals in the moving direction of the latch 22. When the latch 22 is inserted into the limiting hole 13 of each boom under the push of the hydraulic cylinder 23, as shown in FIG. Figure 6 As shown, the sensing part 221 on the latch 22 senses the extended position detection switch 24, causing the extended position detection switch 24 to be triggered and closed, and the retracted position detection switch 25 is in an open state. When the latch 22 is completely withdrawn from the limit hole 13 of each telescopic arm under the pull of the hydraulic cylinder, as shown in FIG. Figure 7 As shown, the sensing portion 221 on the latch 22 senses the retracted position detection switch 25, causing the retracted position detection switch 25 to be triggered to close, and correspondingly the extended position detection switch 24 to be opened.

[0034] like Figure 5 As shown, in this embodiment, the in-position detection switch 24 is used to determine whether the hydraulic cylinder has been in the in-position, that is, whether the latch 22 is inserted into the limit holes 13 of all telescopic arms. When the latch 22 is in the in-position, the induction part 221 on the latch 22 triggers and closes the in-position detection switch 24, the relay K1 is triggered, and the in-position indicator light L1 indicating that the telescopic arm 12 is locked lights up.

[0035] The retracted position detection switch 25 is linked to the master control solenoid valve 35, and the retracted position detection switch 25 is used to determine whether the hydraulic cylinder 23 has been retracted to the position. When the latch 22 withdraws from the limit hole 13 of all telescopic arms 12, the retracted position detection switch 25 is triggered and closed, the relay K2 is triggered, and the indicator light L2 indicating that the boom is unlocked lights up. At the same time, the electromagnetic coil Y3 of the master control solenoid valve 35 is energized, the master control solenoid valve 35 is in the left position, and its oil inlet end is connected to the first oil outlet end and the second oil outlet end at the same time. The oil of the hydraulic pump flows to the pilot control oil circuit 37 and the telescopic switching control valve 33 through the master control solenoid valve 35, and the boarding action is unlocked. The operator can perform boarding actions, such as hoisting and lifting the boom. When the latch 22 is inserted into the limiting hole 13 of all telescopic arms 12, the sensing part 221 on the latch 22 leaves the sensing area of ​​the retracted position detection switch 25, the retracted position detection switch 25 is disconnected, the relay K2 is not triggered, the retracted position indicator L2 is not lit, the electromagnetic coil Y3 of the master control electromagnetic valve 35 is powered off, the oil circuit from the hydraulic pump 32 to the pilot control oil circuit 37 is cut off, the vehicle boarding action is locked, and the operator cannot perform the vehicle boarding operation. Therefore, when the latch is not pulled back to the position by the hydraulic cylinder, the vehicle boarding action is prohibited, thereby preventing the operator from operating the latch device and the boom system from being damaged due to misoperation when the boom is locked.

[0036] In the present invention, the locking operation of the boom is as follows: in the initial state, the latch 22 is in the retracted position. When all telescopic arms are in the unextended state, the operator presses the locking button, the oil cylinder extension switch S1 is closed, and the telescopic switching control valve 33 is in the left position due to the power supply of its electromagnetic coil Y1. The oil output by the hydraulic pump 32 enters the large chamber of the hydraulic cylinder 23 through the master control electromagnetic valve 35, the left position oil circuit of the telescopic switching control valve 33, and the two-way hydraulic lock 34. The piston rod of the hydraulic cylinder 23 extends, pushing the latch 22 to insert into the limit hole 13 of each boom, locking each telescopic arm to prevent it from running out, and at the same time, the extended position indicator L1 indicating that the telescopic arm 12 is locked lights up. When the latch 22 is extended, when the sensing part 221 on the latch 22 leaves the sensing area of ​​the retracted position detection switch 25, the retracted position detection switch 25 is disconnected, the electromagnetic coil Y3 of the master control electromagnetic valve 35 is powered off, the master control electromagnetic valve 35 is switched to the right position, and the vehicle boarding action is locked.

[0037] The unlocking operation of the boom 12 is as follows: the operator presses the unlocking button, the oil cylinder retraction switch S2 is closed, the telescopic switching control valve 33 is in the right position due to the power supply of its electromagnetic coil Y2, the oil output by the hydraulic pump 32 enters the small chamber of the hydraulic cylinder through the master control electromagnetic valve 35, the right position oil circuit of the telescopic switching control valve 33, and the two-way hydraulic lock 34, the piston rod of the hydraulic cylinder 23 retracts, and the bolt 22 is pulled out from the limit hole of each telescopic arm to unlock each telescopic arm. When the bolt 22 is pulled out, when the sensing part 221 on the bolt 22 enters the sensing area of ​​the retracted position detection switch 25, the retracted position detection switch 25 is triggered and closed, the electromagnetic coil Y3 of the master control electromagnetic valve 35 is energized, the master control electromagnetic valve 35 is switched to the left position, and the oil output by the hydraulic pump passes through the right position oil circuit of the master control electromagnetic valve 35 to the pilot control oil circuit, so that the vehicle boarding operation can be performed, and the vehicle boarding action is unlocked.

[0038] In the invention, the boom is locked and unlocked using a latch device, and the operation is simple and convenient.

Claims

1. A truck crane, wherein the lifting arm comprises a multi-section boom, the boom comprising a basic arm and a telescopic arm connected in sequence, characterized in that: A limit hole is provided on each boom section, and the limit holes on each boom section are coaxially aligned when all telescopic arms are in an unextended state; a latch device is installed on the basic arm, and the latch device includes a latch that can be inserted and removed from the limit hole, a driving device for pushing and pulling the latch to insert and remove the latch from the limit hole, and a latch position marking device; The driving device includes a hydraulic cylinder for driving the bolt to move and a hydraulic control oil circuit for controlling the hydraulic cylinder. The bolt device also includes a mounting seat in a cylindrical shape with an end fixed to the basic arm. The bolt and the hydraulic cylinder are mounted in the mounting seat. The hydraulic control oil circuit includes a telescopic switching control valve, a two-way hydraulic lock connected between the telescopic switching control valve and the hydraulic cylinder, a hydraulic pump supplying oil to the telescopic switching control valve, a hydraulic oil tank connected to the hydraulic pump, and a master control solenoid valve; the telescopic switching control valve is a three-position four-way solenoid valve; the two-way hydraulic lock is composed of two hydraulically controlled one-way valves; The oil inlet of the master control solenoid valve is connected to the hydraulic pump, the first oil outlet of the master control solenoid valve is connected to the oil inlet of the telescopic switching control valve, and the second oil outlet of the master control solenoid valve is used to connect to the pilot control oil circuit of the crane vehicle hydraulic system; when the master control solenoid valve is in the left position, the oil inlet of the master control solenoid valve is simultaneously connected to the first oil outlet and the second oil outlet, and when the master control solenoid valve is in the right position, the oil inlet of the master control solenoid valve is connected to the first oil outlet, and the second oil outlet is cut off; when the master control solenoid valve works in the left position, the plugging and unplugging of the bolt and the vehicle boarding operation can be performed; when the master control solenoid valve works in the right position, only the plugging and unplugging of the bolt can be performed, and the vehicle boarding action is prohibited due to the cut-off of the pilot control oil circuit, thereby realizing vehicle boarding locking; The latch position marking device includes an extended position detection switch and a retracted position detection switch linked to the latch position. When the latch is retracted into position, the retracted position detection switch is triggered, and the master control solenoid valve works in the left position; when the latch is not retracted into position, the retracted position detection switch is not triggered, and the master control solenoid valve works in the right position.

2. The truck crane according to claim 1, characterized in that There is a clearance fit between the latch pin and the limiting hole.

3. The truck crane according to claim 1, characterized in that: The extended position detection switch and the retracted position detection switch are respectively connected to a position indicator light.

Images