Vehicle ladder stand system, control method and engineering vehicle

Abstract

The invention discloses a vehicle ladder stand system, a control method and an engineering vehicle, and belongs to the technical field of engineering machinery, and the vehicle ladder stand system comprises a fixing frame, a combined ladder stand, a driving oil cylinder, a hydraulic valve group, a sensor group, an alarm loop and a control loop. The action of the driving oil cylinder is controlled through the control loop under different working conditions, the driving oil cylinder drives the combined crawling ladder to rotate on the vehicle fixing frame, unfolding and folding of the combined crawling ladder are achieved, and when the driving oil cylinder acts, the alarm loop is controlled according to information detected by the sensor set to warn the action of the driving oil cylinder, so that the safety of the combined crawling ladder is improved. The turnover mode that the combined crawling ladder is matched with the driving oil cylinder is adopted, the requirement for the boarding distance is met, and meanwhile the combined crawling ladder is operated under different working conditions through a control loop.

Description

Technical Field

[0001] The invention relates to a vehicle ladder climbing system, a control method and an engineering vehicle, and belongs to the technical field of engineering machinery. Background Art

[0002] Due to its huge structure, the cab of a high-horsepower grader is high from the ground. Take XCMG GR5505 as an example. Its cab is nearly 3.3 meters from the ground. Ordinary boarding ladders cannot meet the normal up and down requirements of operators. The normal up and down are from the rear of the whole machine, and a special safety passage needs to be built. The operator walks around the vehicle when getting on or off the vehicle, which consumes too much time and extra physical strength. In addition, the existing hydraulic flip ladder cannot consider the various working conditions of the vehicle for flipping operations, which poses a safety hazard. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a vehicle ladder system, a control method and an engineering vehicle. A combined ladder is used in conjunction with a flipping driving cylinder to satisfy the requirements of the boarding distance while allowing the combined ladder to be operated under different working conditions through a control circuit. This solves the problem that the current engineering machinery boarding ladder occupies too much space, cannot be operated according to different working conditions of the vehicle, and poses a safety hazard.

[0004] In order to solve the above technical problems, the present invention is implemented by adopting the following technical solutions: A first aspect of the present invention provides a vehicle ladder system, comprising: A fixing frame, arranged on one side of the vehicle body; A combined ladder, hinged to the fixed frame; A driving cylinder, used for driving the combined ladder to flip, so as to change the angle between the combined ladder and the fixing frame; A hydraulic valve group, connected to the driving cylinder, for switching the action of the driving cylinder by changing the direction of the hydraulic circuit; A sensor group, comprising a first sensor for detecting a combined ladder lifting position signal and a second sensor for detecting a combined ladder descending position signal; The control circuit is used to control the action of the hydraulic valve group to change the direction of the hydraulic circuit, and control the alarm circuit to output an alarm according to the signal detected by the sensor group.

[0005] Optionally, the combined ladder comprises a first driven mechanism, a first ladder body, a second driven mechanism, a second ladder body and a pull rod for pulling the second driven mechanism; The first driven mechanism is movably arranged on the fixed frame, one end of the first driven mechanism is movably connected to the movable end of the driving cylinder, and the other end of the first driven mechanism is movably connected to the first ladder body; One end of the first ladder body is hinged to the fixed frame, the second follower mechanism is movably arranged at the other end of the first ladder body, and the second follower mechanism is connected to the fixed frame through a pull rod; The second ladder body is hinged to one end of the first ladder body away from the fixing frame and is movably connected to the second driven mechanism.

[0006] Optionally, the first driven mechanism includes a main arm and a swing arm hinged on a fixed frame; one end of the main arm is hinged to the movable end of the driving cylinder, and the other end is hinged to the swing arm, and the end of the swing arm away from the main arm is hinged to the first ladder body.

[0007] Optionally, the second driven mechanism includes a triangular connecting plate and a straight plate hinged to the triangular connecting plate; one end of the triangular connecting plate is hinged to the pull rod and the other end is hinged to the first ladder body, one end of the pull rod away from the triangular connecting plate is hinged to the fixed frame, and one end of the straight plate away from the triangular connecting plate is hinged to the second ladder body.

[0008] Optionally, the hydraulic valve group includes a valve body, an electromagnetic control valve arranged on the valve body for switching the oil inlet or oil return of the valve body, and an electromagnetic one-way valve arranged on the valve body for switching the oil inlet or oil return of the driving cylinder.

[0009] Optionally, the valve body is provided with a first oil inlet and an oil outlet R / L; the solenoid control valve is provided with an oil inlet P, an oil return port T and a first oil outlet; the solenoid check valve is provided with a second oil inlet and a second oil outlet; the oil return port T is connected to the vehicle hydraulic oil tank, and the first oil outlet of the solenoid control valve is connected to the first oil inlet of the valve body. When the oil return port T is opened, the vehicle hydraulic oil tank is connected to the valve body through the oil return port T, the first oil outlet and the first oil inlet, and the oil inlet P is connected to the vehicle hydraulic pump. When the oil inlet P is opened, the vehicle hydraulic pump is connected to the valve body through the oil inlet P, the first oil outlet and the first oil inlet; the oil outlet R / L is connected to the second oil inlet of the solenoid check valve, and the second oil outlet of the solenoid check valve is connected to the driving cylinder. When the oil outlet R / L is opened, the driving cylinder is connected to the valve body through the second oil outlet, the second oil inlet and the oil outlet R / L.

[0010] Optionally, the control circuit includes an on-board power supply, an activation relay, a latching relay and a control switch group; The control switch group includes a first control switch, a second control switch and a third control switch; The alarm circuit includes a buzzer circuit and an external alarm circuit; The buzzer circuit includes a buzzer relay and a first buzzer, and the external alarm circuit includes an external alarm relay, an indicator light and a second buzzer; The positive electrode of the vehicle power supply is electrically connected to the third control switch, the activation relay input terminal, the first sensor input terminal, the second sensor input terminal and the external alarm relay input terminal respectively; The third control switch is electrically connected to the input terminal of the activation relay; The activation relay output end is electrically connected to the negative electrode of the power supply and the second control switch respectively; The second control switch is electrically connected to the input terminal of the latching relay; The output end of the first sensor is connected to a diode A, and the diode A is electrically connected to the input end of the latch relay and the input end of the buzzer relay respectively; The buzzer relay output end is electrically connected to the first buzzer, the electromagnetic one-way valve input end and the negative pole of the power supply respectively, and the first buzzer is electrically connected to the negative pole of the power supply; The output end of the electromagnetic one-way valve is electrically connected to the first control switch, the first control switch is electrically connected to the input end of the electromagnetic control valve and the input end of the latching relay respectively, and the output end of the electromagnetic control valve is electrically connected to the negative pole of the power supply; The output end of the second sensor is electrically connected to the input end of the external alarm relay, and the output end of the external alarm relay is electrically connected to the second buzzer and the negative pole of the vehicle power supply respectively; The output end of the second sensor is also electrically connected to a diode B, the output end of the diode B is electrically connected to a diode C, the output end of the diode C is electrically connected to a diode D, and the output end of the diode D is electrically connected to the negative pole of the vehicle power supply; The output end of the latching relay is electrically connected to the indicator light, the diode D, and the negative pole of the vehicle power supply respectively; The indicator light is electrically connected to the negative pole of the vehicle-mounted power supply.

[0011] Optionally, the control loop further includes a tool control branch; The implement control branch includes a parking switch, an implement switch, and an interlock relay; One end of the parking switch is electrically connected to the input end of the buzzer relay, and the other end is connected to the positive pole of the vehicle power supply; The implement switch comprises an unlocked end, a locked end and a common end; The input end of the interlock relay is electrically connected to the PWR of the vehicle tool control module, wherein the vehicle tool control module is used to control the vehicle tool; The output end of the interlock relay is electrically connected to the input end, the unlocked end, and the diode C of the vehicle-mounted tool control module respectively; The common terminal is connected to the PWR of the vehicle-mounted implement control module; When the implement switch is in the unlocked end, the vehicle implement is unlocked.

[0012] A second aspect of the present invention provides a control method for a vehicle ladder system, comprising: Press the first control switch to extend the movable end of the drive cylinder, the combination ladder rotates upward, and the first and second buzzers sound, and the indicator light flashes. When the combination ladder rotates to the first sensor detection position, the drive cylinder stops extending, the first and second buzzers and the indicator light turn off, and the implement switch can be switched to the unlocked end. When the implement switch is switched to the unlocked end, the parking switch is unlocked; Press the second control switch to drive the movable end of the oil cylinder to retract, the combined ladder rotates downward, and the first buzzer and the second buzzer sound, and the indicator light flashes. When the combined ladder rotates to the second sensor detection position, the first buzzer, the second buzzer and the indicator light turn off, and the machine switch is at the locking end. Press the third control switch to drive the movable end of the oil cylinder to retract, and the combined ladder rotates downward; When the vehicle-mounted power supply is cut off, the movable end of the driving cylinder is retracted and the combined ladder rotates downward.

[0013] A third aspect of the present invention provides an engineering vehicle, comprising the above-mentioned vehicle ladder system.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention controls the action of the driving cylinder under different working conditions through a control circuit, and the driving cylinder drives the combined ladder to rotate on the vehicle fixing frame to realize the unfolding and folding of the combined ladder. When the driving cylinder is in motion, the alarm circuit is controlled according to the information detected by the sensor group to warn the action of the driving cylinder. The combined ladder is used in conjunction with the turning form of the driving cylinder. While meeting the boarding distance requirements, the control circuit is used to operate the combined ladder under different working conditions, thereby solving the problem that the boarding ladder of current engineering machinery occupies too much space, cannot be operated according to different working conditions of the vehicle, and has potential safety hazards; 2. When the vehicle power supply is cut off or the vehicle fails and the third control switch is pressed, the electromagnetic control valve and the electromagnetic one-way valve are de-energized, so that the return oil port and the oil outlet R / L are opened, and the movable end of the driving cylinder is retracted, and finally the combined ladder is rotated downward and unfolded, so that it is convenient to get on the vehicle for inspection and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a front view of a vehicle climbing system, a control method and an engineering vehicle according to an embodiment of the present invention; Figure 2 It is a rear view of a vehicle ladder system according to an embodiment of the present invention, a control method and an engineering vehicle; Figure 3It is a structural schematic diagram of a hydraulic valve group of a vehicle climbing system in an embodiment of a vehicle climbing system, a control method and an engineering vehicle of the present invention; Figure 4 It is a structural schematic diagram of a control circuit and an alarm circuit of a vehicle climbing system in accordance with an embodiment of a vehicle climbing system, a control method and an engineering vehicle of the present invention; Figure 5 The present invention is a schematic diagram of a folding vehicle ladder system, a control method and an engineering vehicle embodiment of the present invention.

[0016] In the figure: 1, fixed frame; 2, combined ladder; 201, first driven mechanism; 2011, main arm; 2012, swing arm; 202, first ladder body; 203, second driven mechanism; 2031, triangular connecting plate; 2032, straight plate; 204, second ladder body; 205, pull rod; 3, driving cylinder; 4, hydraulic valve group; 401, valve body; 402, electromagnetic control valve; 403, electromagnetic check valve; 404, oil inlet P; 405, oil return port T; 406, oil outlet R / L; 5, sensor group; 501, first sensor; 502, second sensor; 6001, vehicle power supply; 6002, activation relay; 6003, latching relay; 6004, first control switch; 6005, first Second control switch; 6006, third control switch; 6007, buzzer relay; 6008, first buzzer; 6009, external alarm relay; 6010, indicator light; 6011, second buzzer; 6012, parking switch; 6013, unlocked end; 6014, locked end; 6015, common end; 6016, interlock relay; 7, diode A; 8, diode B; 9, diode C; 10, diode D; 11, vehicle-mounted equipment control module. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0018] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances. Example

[0019] A vehicle ladder system, comprising: a fixed frame 1, a combined ladder 2, a driving cylinder 3, a hydraulic valve group 4, a sensor group 5, an alarm circuit and a control circuit; wherein the fixed frame 1 is fixedly installed on one side of the vehicle body; like Figure 1 and Figure 2 As shown, the combined ladder 2 includes a first driven mechanism 201, a first ladder body 202, a second driven mechanism 203, a second ladder body 204 and a pull rod 205 for pulling the second driven mechanism 203. Specifically: The first driven mechanism 201 includes a main arm 2011 and a swing arm 2012; the top of the main arm 2011 is hinged to the bottom of the fixed frame 1, the fixed end of the driving cylinder 3 is hinged to the bottom of the fixed frame 1, the movable end of the driving cylinder 3 is hinged to the rear end of the main arm 2011, the front end of the main arm 2011 is hinged to the rear end of the swing arm 2012, and the front end of the swing arm 2012 is hinged to the side of the first ladder body 202; The second driven mechanism 203 includes a triangular connecting plate 2031 and a straight plate 2032; the top end of the triangular connecting plate 2031 is hinged to one end of the pull rod 205, and the other end of the pull rod 205 is hinged to the fixing frame 1; The rear end of the triangular connecting plate 2031 is hinged to the side of the first ladder body 202, and the front end of the triangular connecting plate 2031 is hinged to one end of the straight plate 2032; One end of the straight plate 2032 away from the triangular connecting plate 2031 is hinged to the side surface of the second ladder body 204; The top end of the second ladder body 204 is hinged to the bottom end of the first ladder body 202, and the top end of the first ladder body 202 is hinged to the fixing frame 1; like Figure 3 As shown, the hydraulic valve group 4 includes a valve body 401, an electromagnetic control valve 402 provided on the valve body 401 for switching the oil inlet or oil return of the valve body 401, and an electromagnetic one-way valve 403 provided on the valve body 401 for switching the oil inlet or oil return of the driving cylinder 3. Specifically: The valve body 401 is provided with a first oil inlet and an oil outlet R / L406; the solenoid control valve 402 is provided with an oil inlet P404, an oil return port T405 and a first oil outlet; the solenoid check valve 403 is provided with a second oil inlet and a second oil outlet; the oil return port T405 is connected to the vehicle hydraulic oil tank, and the first oil outlet of the solenoid control valve 402 is connected to the first oil inlet of the valve body 401. When the oil return port T405 is opened, the vehicle hydraulic oil tank is connected to the valve body 401 through the oil return port T405, the first oil outlet, the first oil inlet, and the oil return port T405. 1 is connected, the oil inlet P404 is connected to the vehicle hydraulic pump; when the oil inlet P404 is opened, the vehicle hydraulic pump is connected to the valve body 401 through the oil inlet P404, the first oil outlet, and the first oil inlet; the oil outlet R / L406 is connected to the second oil inlet of the electromagnetic one-way valve 403, and the second oil outlet of the electromagnetic one-way valve 403 is connected to the driving cylinder 3. When the oil outlet R / L406 is opened, the driving cylinder 3 is connected to the valve body 401 through the second oil outlet, the second oil inlet, and the oil outlet R / L406; In this example, the driving cylinder 3 is a single-channel cylinder, and oil inlet and oil return are realized through the oil outlet R / L406. A spring is installed inside the driving cylinder 3, and the spring is connected to the movable end. When the movable end is extended, the spring is compressed; The sensor includes a first sensor 501 and a second sensor 502 mounted on the fixing frame 1. The first sensor 501 and the second sensor 502 can detect the position of the combined ladder 2. In this embodiment, the first sensor 501 and the second sensor 502 are both proximity switch sensors; like Figure 4 As shown, the control circuit includes an on-board power supply 6001, an activation relay 6002, a latching relay 6003 and a control switch group, specifically: The control switch group includes a first control switch 6004, a second control switch 6005 and a third control switch 6006; the alarm circuit includes a buzzer circuit and an external alarm circuit; The buzzer circuit includes a buzzer relay 6007 and a first buzzer 6008, and the external alarm circuit includes an external alarm relay 6009, an indicator light 6010 and a second buzzer 6011; The positive electrode of the vehicle power supply 6001 is electrically connected to the third control switch 6006, the input end of the activation relay 6002, the input end of the first sensor 501, the input end of the second sensor 502, and the input end of the external alarm relay 6009 respectively; The third control switch 6006 is electrically connected to the input terminal of the activation relay 6002; The output end of the activation relay 6002 is electrically connected to the negative electrode of the power supply and the second control switch 6005 respectively; The second control switch 6005 is electrically connected to the input terminal of the latching relay 6003; The output end of the first sensor 501 is connected to a diode A7, and the diode A7 is electrically connected to the input end of the latch relay 6003 and the input end of the buzzer relay 6007 respectively; The output end of the buzzer relay 6007 is electrically connected to the first buzzer 6008, the input end of the electromagnetic one-way valve 403 and the negative pole of the power supply respectively, and the first buzzer 6008 is electrically connected to the negative pole of the vehicle power supply 6001; The output end of the electromagnetic check valve 403 is electrically connected to the first control switch 6004, the first control switch 6004 is electrically connected to the input end of the electromagnetic control valve 402 and the input end of the latching relay 6003 respectively, and the output end of the electromagnetic control valve 402 is electrically connected to the negative pole of the power supply; The output end of the second sensor 502 is electrically connected to the input end of the external alarm relay 6009, and the output end of the external alarm relay 6009 is electrically connected to the second buzzer 6011 and the negative pole of the vehicle power supply 6001 respectively; The output end of the second sensor 502 is also electrically connected to a diode B8, the output end of the diode B8 is electrically connected to a diode C9, the output end of the diode C9 is electrically connected to a diode D10, and the output end of the diode D10 is electrically connected to the negative pole of the vehicle power supply 6001; The output end of the latching relay 6003 is electrically connected to the indicator light 6010, the diode D10, and the negative pole of the vehicle power supply 6001 respectively; The indicator light 6010 is electrically connected to the negative pole of the vehicle power supply 6001; The control circuit also includes a machine control branch, which includes a parking switch 6012, a machine switch, and an interlock relay 6016; One end of the parking switch 6012 is electrically connected to the input end of the buzzer relay 6007, and the other end is connected to the positive electrode of the vehicle power supply 6001; The implement switch includes an unlocked end 6013, a locked end 6014 and a common end 6015; The input end of the interlock relay 6016 is electrically connected to the PWR of the vehicle-mounted implement control module 11, wherein the vehicle-mounted implement control module 11 is used to control vehicle implements and is a device carried by existing engineering vehicles; The output end of the interlock relay 6016 is electrically connected to the input end of the vehicle-mounted implement control module 11, the unlocking end 6013, and the diode C9 respectively; The common terminal 6015 is connected to the PWR of the vehicle-mounted implement control module 11; When the implement switch is at the unlocked end 6013, the vehicle implement is unlocked. In this embodiment, the vehicle is a grader, and the implement is a blade and a slewing circle; like Figure 5As shown, when the first control switch 6004 is closed, the electromagnetic control valve 402 is energized, the electromagnetic check valve 403 is de-energized, the oil inlet P404 and the oil outlet R / L406 are opened, and the movable end of the driving cylinder 3 is extended. After the movable end of the driving cylinder 3 is extended, the main arm 2011 drives the combined ladder 2 to rotate upward as a whole through the swing arm 2012, wherein the first ladder body 202 rotates upward, and driven by the pull rod 205, the triangular connecting plate 2031 and the straight plate 2032, the second ladder body 204 moves upward following the first ladder body 202. After rising to a certain height, the second ladder body 204 is turned downward by the action of gravity, and the combined ladder 2 is folded; When the second control switch 6005 is closed, the electromagnetic control valve 402 is de-energized, the electromagnetic check valve 403 is de-energized, the oil return port T405 and the oil outlet R / L406 are opened, and the movable end of the driving cylinder 3 is retracted; When the third control switch 6006 is closed, the electromagnetic control valve 402 is de-energized, the electromagnetic check valve 403 is de-energized, the oil return port T405 and the oil outlet R / L406 are opened, and the movable end of the driving cylinder 3 is retracted; When the movable end of the driving cylinder 3 is shortened, the combined ladder 2 rotates downward as a whole. When the first ladder body 202 descends to a certain height, the second ladder body 204 rotates and the combined ladder 2 is unfolded. Example

[0020] A control method for a vehicle ladder system, comprising: When the vehicle is parked, the first control switch 6004 is pressed, the movable end of the driving cylinder 3 is extended, the combined ladder 2 rotates upward, and the first buzzer 6008 and the second buzzer 6011 make sounds, and the indicator light 6010 flashes. When the combined ladder 2 rotates to the detection position of the first sensor 501, the driving cylinder 3 stops extending, the first buzzer 6008, the second buzzer 6011 and the indicator light 6010 are turned off, and the machine switch can be switched to the unlocked end 6013. When the machine switch can be switched to the unlocked end 6013, the parking switch 6012 is unlocked; When the vehicle is parked, the second control switch 6005 is pressed to drive the movable end of the oil cylinder 3 to retract, the combined ladder 2 rotates downward, and the first buzzer 6008 and the second buzzer 6011 make sounds, and the indicator light 6010 flashes. When the combined ladder 2 rotates to the detection position of the second sensor 502, the first buzzer 6008, the second buzzer 6011 and the indicator light 6010 are turned off, and the machine switch is at the locking end 6014; When the vehicle encounters an emergency, such as when the engine is turned off or the vehicle encounters a fault, the third control switch 6006 is pressed to drive the movable end of the oil cylinder 3 to retract and the combined ladder 2 to rotate downward; When the vehicle-mounted power supply 6001 is powered off, the movable end of the driving cylinder 3 is retracted and the combined ladder 2 rotates downward. Example

[0021] An engineering vehicle comprises the above-mentioned vehicle ladder system.

[0022] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A vehicle ladder system, characterized in that: include: A fixing frame (1) is arranged on one side of the vehicle body; A combined ladder (2) is hinged to the fixed frame (1); A driving cylinder (3) for driving the combined ladder (2) to flip, so as to change the angle between the combined ladder (2) and the fixed frame (1); A hydraulic valve group (4) connected to the driving cylinder (3) and used to switch the action of the driving cylinder (3) by changing the direction of the hydraulic circuit; A sensor group (5) comprising a first sensor (501) for detecting a rising position signal of the combined ladder (2) and a second sensor (502) for detecting a falling position signal of the combined ladder (2); The control circuit is used to control the action of the hydraulic valve group (4) to change the direction of the hydraulic circuit, and to control the alarm circuit to output an alarm according to the signal detected by the sensor group (5).

2. The vehicle ladder system according to claim 1, characterized in that: The combined ladder (2) comprises a first driven mechanism (201), a first ladder body (202), a second driven mechanism (203), a second ladder body (204), and a pull rod (205) for pulling the second driven mechanism (203); The first driven mechanism (201) is movably arranged on the fixed frame (1); one end of the first driven mechanism (201) is movably connected to the movable end of the driving cylinder (3), and the other end is movably connected to the first ladder body (202); One end of the first ladder body (202) is hinged to the fixed frame (1), the second driven mechanism (203) is movably arranged at the other end of the first ladder body (202), and the second driven mechanism (203) is connected to the fixed frame (1) via a pull rod (205); The second ladder body (204) is hinged to an end of the first ladder body (202) away from the fixing frame (1) and is movably connected to the second driven mechanism (203).

3. The vehicle ladder system according to claim 2, characterized in that: The first driven mechanism (201) comprises a main arm (2011) and a swing arm (2012) which are hinged on a fixed frame (1); one end of the main arm (2011) is hinged to the movable end of the driving cylinder (3), and the other end is hinged to the swing arm (2012); and one end of the swing arm (2012) away from the main arm (2011) is hinged to the first ladder body (202).

4. The vehicle ladder system according to claim 2, characterized in that: The second driven mechanism (203) comprises a triangular connecting plate (2031) and a straight plate (2032) hinged to the triangular connecting plate (2031); one end of the triangular connecting plate (2031) is hinged to the pull rod (205), and the other end is hinged to the first ladder body (202); one end of the pull rod (205) away from the triangular connecting plate (2031) is hinged to the fixed frame (1); and one end of the straight plate (2032) away from the triangular connecting plate (2031) is hinged to the second ladder body (204).

5. The vehicle ladder system according to claim 1, characterized in that: The hydraulic valve group (4) comprises a valve body (401), an electromagnetic control valve (402) provided on the valve body (401) for switching the oil inlet or oil return of the valve body (401), and an electromagnetic one-way valve (403) provided on the valve body (401) for switching the oil inlet or oil return of the driving oil cylinder (3).

6. The vehicle ladder system according to claim 5, characterized in that: The valve body (401) is provided with a first oil inlet and an oil outlet R / L (406); the solenoid control valve (402) is provided with an oil inlet P (404), an oil return port T (405) and a first oil outlet; the solenoid check valve (403) is provided with a second oil inlet and a second oil outlet; the oil return port T (405) is connected to the vehicle hydraulic oil tank, and the first oil outlet of the solenoid control valve (402) is connected to the first oil inlet of the valve body (401); when the oil return port T (405) is opened, the vehicle hydraulic oil tank is connected to the valve body (401) via the oil return port T (405), the first oil outlet, the first oil inlet, and the oil supply port. 1) connected, the oil inlet P (404) is connected to the vehicle hydraulic pump, when the oil inlet P (404) is opened, the vehicle hydraulic pump is connected to the valve body (401) through the oil inlet P (404), the first oil outlet, and the first oil inlet; the oil outlet R / L (406) is connected to the second oil inlet of the electromagnetic one-way valve (403), the second oil outlet of the electromagnetic one-way valve (403) is connected to the driving cylinder (3), when the oil outlet R / L (406) is opened, the driving cylinder (3) is connected to the valve body (401) through the second oil outlet, the second oil inlet, and the oil outlet R / L (406).

7. The vehicle ladder system according to claim 5, characterized in that: The control circuit includes an on-board power supply (6001), an activation relay (6002), a latching relay (6003) and a control switch group; The control switch group comprises a first control switch (6004), a second control switch (6005) and a third control switch (6006); The alarm circuit comprises a buzzer circuit and an external alarm circuit; the buzzer circuit comprises a buzzer relay (6007) and a first buzzer (6008), and the external alarm circuit comprises an external alarm relay (6009), an indicator light (6010) and a second buzzer (6011); The positive electrode of the vehicle-mounted power supply (6001) is electrically connected to the third control switch (6006), the activation relay (6002) input terminal, the first sensor (501) input terminal, the second sensor (502) input terminal and the external alarm relay (6009) input terminal respectively; The third control switch (6006) is electrically connected to the input terminal of the activation relay (6002); The output end of the activation relay (6002) is electrically connected to the negative electrode of the power supply and the second control switch (6005) respectively; The second control switch (6005) is electrically connected to an input terminal of the latching relay (6003); The output end of the first sensor (501) is connected to a diode A (7), and the diode A (7) is electrically connected to the input end of the latching relay (6003) and the input end of the buzzer relay (6007) respectively; The output end of the buzzer relay (6007) is electrically connected to the first buzzer (6008), the input end of the electromagnetic one-way valve (403) and the negative pole of the power supply respectively, and the first buzzer (6008) is electrically connected to the negative pole of the power supply; The output end of the electromagnetic one-way valve (403) is electrically connected to the first control switch (6004), the first control switch (6004) is electrically connected to the input end of the electromagnetic control valve (402) and the input end of the latching relay (6003), respectively, and the output end of the electromagnetic control valve (402) is electrically connected to the negative pole of the power supply; The output end of the second sensor (502) is electrically connected to the input end of the external alarm relay (6009), and the output end of the external alarm relay (6009) is electrically connected to the second buzzer (6011) and the negative pole of the vehicle power supply (6001) respectively; The output end of the second sensor (502) is also electrically connected to a diode B (8), the output end of the diode B (8) is electrically connected to a diode C (9), the output end of the diode C (9) is electrically connected to a diode D (10), and the output end of the diode D (10) is electrically connected to the negative pole of the vehicle power supply (6001); The output end of the latching relay (6003) is electrically connected to the indicator light (6010), the diode D (10), and the negative pole of the vehicle power supply (6001) respectively; The indicator light (6010) is electrically connected to the negative pole of the vehicle power supply (6001).

8. The vehicle ladder system according to claim 7, characterized in that: The control loop also includes a tool control branch; The implement control branch includes a parking switch (6012), an implement switch, and an interlock relay (6016); One end of the parking switch (6012) is electrically connected to the input end of the buzzer relay (6007), and the other end is connected to the positive electrode of the vehicle power supply (6001); The tool switch comprises an unlocked end (6013), a locked end (6014) and a common end (6015); The input end of the interlock relay (6016) is electrically connected to the PWR of the vehicle-mounted implement control module (11), wherein the vehicle-mounted implement control module (11) is used to control the vehicle implement; The output end of the interlock relay (6016) is electrically connected to the input end of the vehicle-mounted tool control module (11), the unlocked end (6013), and the diode C (9) respectively; The common terminal (6015) is connected to the PWR of the vehicle-mounted implement control module (11); When the implement switch is in the unlocked end (6013), the vehicle implement is unlocked.

9. A control method for a vehicle ladder system as claimed in claim 8, characterized in that: include: When the first control switch (6004) is pressed, the movable end of the driving cylinder (3) is extended, the combined ladder (2) rotates upward, and at the same time, the first buzzer (6008) and the second buzzer (6011) sound, and the indicator light (6010) flashes. When the combined ladder (2) rotates to the detection position of the first sensor (501), the driving cylinder (3) stops extending, the first buzzer (6008), the second buzzer (6011) and the indicator light (6010) are turned off, and at this time, the machine switch can be switched to the unlocked end (6013). When the machine switch is switched to the unlocked end (6013), the parking switch (6012) is unlocked; The second control switch (6005) is pressed to drive the movable end of the oil cylinder (3) to retract, the combined ladder (2) rotates downward, and at the same time, the first buzzer (6008) and the second buzzer (6011) sound, and the indicator light (6010) flashes. When the combined ladder (2) rotates to the detection position of the second sensor (502), the first buzzer (6008), the second buzzer (6011) and the indicator light (6010) are turned off, and the machine switch is at the locking end (6014). Pressing the third control switch (6006) drives the movable end of the oil cylinder (3) to retract, and the combined ladder (2) rotates downward; When the vehicle power supply (6001) is powered off, the movable end of the driving cylinder (3) is retracted and the combined ladder (2) rotates downward.

10. An engineering vehicle, characterized in that: The vehicle ladder system comprises the vehicle ladder system as described in any one of claims 1-8.

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