阅读说明：本技术 一种剪叉升降搬运车工作平台的控制系统 (Control system of working platform of scissor lifting carrier ) 是由 陈德义 石磊 于 2020-07-27 设计创作，主要内容包括：本申请公开了一种剪叉升降搬运车工作平台的控制系统,包括第一换向阀、油缸、背压阀、直流电机、定量泵和油箱；第一换向阀具有A口、B口、P口和T口,第一换向阀的A口与油缸的无杆腔连接,第一换向阀的B口与油缸的有杆腔连接,第一换向阀的P口与定量泵的油液出口连接,第一换向阀的T口与油箱的进口连接,背压阀设于第一换向阀的A口与油缸的无杆腔之间的液压管路上,直流电机的驱动轴与定量泵的泵轴固定连接。本申请提供的剪叉升降搬运车工作平台的控制系统通过增加背压阀和直流电机调速,消除升降平台在升降过程中的抖动和失速。(The application discloses a control system of a working platform of a scissor lifting carrier, which comprises a first reversing valve, an oil cylinder, a back pressure valve, a direct current motor, a constant delivery pump and an oil tank; the first reversing valve is provided with an A port, a B port, a P port and a T port, the A port of the first reversing valve is connected with a rodless cavity of the oil cylinder, the B port of the first reversing valve is connected with a rod cavity of the oil cylinder, the P port of the first reversing valve is connected with an oil outlet of the constant delivery pump, the T port of the first reversing valve is connected with an inlet of the oil tank, the back pressure valve is arranged on a hydraulic pipeline between the A port of the first reversing valve and the rodless cavity of the oil cylinder, and a driving shaft of the direct current motor is fixedly connected with a pump shaft of the constant delivery pump. The application provides a control system of scissors fork lift carrier work platform eliminates the shake and the stall of lift platform at the lift in-process through increasing back pressure valve and direct current motor speed governing.)

1. A control system of a working platform of a scissor lifting carrier is characterized by comprising a first reversing valve (3), an oil cylinder (1), a back pressure valve (4), a direct current motor (10), a constant delivery pump (7) and an oil tank (12); first switching-over valve (3) have A mouth, B mouth, P mouth and T mouth, the A mouth of first switching-over valve (3) with the rodless chamber of hydro-cylinder (1) is connected, the B mouth of first switching-over valve (3) with the pole chamber of hydro-cylinder (1) is connected, the P mouth of first switching-over valve (3) with the fluid exit linkage of constant delivery pump (7), the T mouth of first switching-over valve (3) with the access connection of oil tank (12), back pressure valve (4) are located the A mouth of first switching-over valve (3) with on the hydraulic pressure pipeline between the rodless chamber of hydro-cylinder (1), the drive shaft of direct current motor (10) with the pump shaft fixed connection of constant delivery pump (7).

2. The control system of a scissors lift truck work platform of claim 1, further comprising a hall handle (14), a controller and a driver (15); the Hall handle (14) comprises a handle body and a Hall sensor, the Hall sensor is electrically connected with the controller, and the Hall sensor outputs corresponding analog signals to the controller according to the movement distance of the handle body; the controller is electrically connected with the driver (15), and converts the analog signal into PWM pulse and sends the PWM pulse to the driver (15); the driver (15) is electrically connected with the direct current motor (10), and the driver (15) outputs a corresponding armature voltage signal to the direct current motor (10) according to the PWM pulse.

3. Control system of a scissor lift truck work platform according to claim 1, characterized in that the back pressure valve (4) comprises:

the valve body (41) is in a tubular shape with a valve body inner cavity (411) inside, and a limiting bulge (412) is arranged on the side wall of the valve body inner cavity (411);

the first joint (42) is arranged at the first end of the valve body (41), a first joint flow channel (421) is arranged in the first joint, one end of the first joint flow channel (421) is a P port, and the other end of the first joint flow channel is a first joint inner port (422) communicated with the valve body inner cavity (411); a first joint through hole (423) extends from an outer side wall of the first joint (42) to the first joint flow passage (421), and the first joint through hole (423) communicates with the valve body inner cavity (411);

the second joint (43) is arranged at the second end of the valve body (41), a second joint flow channel (431) is arranged in the second joint, one end of the second joint flow channel (431) is an A port, and the other end of the second joint flow channel is a second joint inner port communicated with the valve body inner cavity (411);

the valve core (44) is in a tubular shape with a valve core inner cavity (443) inside, is arranged inside the valve body (41), and comprises a first section (441) and a second section (442), a gap is formed between the first section (441) and the inner side wall of the valve body (41), the second section (442) is in sealing connection with the inner side wall of the valve body (41), and a valve core through hole (444) extends from the valve core inner cavity (443) to the outer side wall of the first section (441);

a steel ball (45) provided between the first section (441) and the first joint inner interface (422);

and the spring (46) is arranged in the valve body (41) and pushes the valve core (44) towards the first section (441) so that the first section (441) is abutted against the limiting bulge (412).

4. The control system of a scissor lift truck work platform according to claim 1, wherein a first orifice is provided in the hydraulic line between the back pressure valve (4) and the port a of the first direction valve (3), and a second orifice is provided in the hydraulic line between the port B of the first direction valve (3) and the rod chamber of the cylinder (1).

5. A control system of a scissor lift truck work platform according to any one of claims 1 to 4, further comprising a second directional control valve (5), wherein the second directional control valve (5) has an A port, a B port, a P port and a T port, the A port of the second directional control valve (5) is connected with a plug (13), the B port of the second directional control valve (5) is connected with the P port of the first directional control valve (3), the P port of the second directional control valve (5) is connected with the oil outlet of the dosing pump (7), and the T port of the second directional control valve (5) is connected with the inlet of the oil tank (12).

6. The control system of a scissor lift truck work platform according to claim 5, wherein the second directional valve (5) is a two-position four-way valve and the first directional valve (3) is a three-position four-way solenoid valve.

7. A control system of a scissor lift truck work platform according to claim 5, wherein a first overflow valve (2) is provided between the port B of the second directional control valve (5) and the port P of the first directional control valve (3).

8. A control system of a scissor lift truck work platform according to claim 5, wherein a check valve (6) is provided between the port P of the second directional valve (5) and the oil outlet of the dosing pump (7).

9. A control system of a scissor lift truck work platform according to claim 8, wherein a second relief valve (11) is provided between the oil outlet of the dosing pump (7) and the inlet of the check valve (6).

Technical Field

The application relates to the technical field of scissor forks, in particular to a control system of a working platform of a scissor fork lifting carrier.

Background

With the rapid development of artificial intelligence and big data, the number and the types of computer servers are more and more. The server is installed and replaced, and a scissor lifting carrier needs to be used in the transferring process to carry the server to be placed on a goods shelf. At present, part of clients can customize a shelf according to the size of a server, the gap between the server and the shelf is small, and a plurality of layers of shelves are arranged above and below the server and the server, so that the low-speed requirement on the lift truck is very high.

Disclosure of Invention

In view of this, an object of the present application is to provide a control system for a working platform of a scissors lifting truck, which adopts a back pressure valve and a dc motor to regulate speed, so as to eliminate the jitter and stall of the lifting platform of the scissors during the lifting process.

In order to achieve the above purpose, the present application provides the following technical solutions:

a control system of a working platform of a scissor lifting carrier comprises a first reversing valve, an oil cylinder, a back pressure valve, a direct current motor, a constant delivery pump and an oil tank; first switching-over valve has A mouth, B mouth, P mouth and T mouth, the A mouth of first switching-over valve with the rodless chamber of hydro-cylinder is connected, the B mouth of first switching-over valve with the pole chamber of hydro-cylinder is connected, the P mouth of first switching-over valve with the fluid exit linkage of constant delivery pump, the T mouth of first switching-over valve with the access connection of oil tank, the back pressure valve is located the A mouth of first switching-over valve with on the hydraulic pressure pipeline between the rodless chamber of hydro-cylinder, direct current motor's drive shaft with the pump shaft fixed connection of constant delivery pump.

Optionally, the device comprises a Hall handle, a controller and a driver; the Hall handle comprises a handle body and a Hall sensor, the Hall sensor is electrically connected with the controller, and the Hall sensor outputs corresponding analog signals to the controller according to the moving distance of the handle body; the controller is electrically connected with the driver and converts the analog signal into PWM pulse and sends the PWM pulse to the driver; the driver is electrically connected with the direct current motor, and the driver outputs corresponding armature voltage signals to the direct current motor according to the PWM pulses.

Optionally, the back pressure valve comprises:

the valve body is tubular, the interior of the valve body is provided with a valve body inner cavity, and the side wall of the valve body inner cavity is provided with a limiting bulge;

the first connector is arranged at the first end of the valve body, a first connector flow channel is arranged in the first connector, one end of the first connector flow channel is a P port, and the other end of the first connector flow channel is a first connector inner port communicated with the inner cavity of the valve body; a first joint through hole extends from the outer side wall of the first joint to the first joint flow channel, and the first joint through hole is communicated with the inner cavity of the valve body;

the second connector is arranged at the second end of the valve body, a second connector flow channel is arranged in the second connector, one end of the second connector flow channel is an A port, and the other end of the second connector flow channel is a second connector inner port communicated with the inner cavity of the valve body;

the valve core is tubular, the inner cavity of the valve core is formed in the valve core, the valve core is arranged in the valve body and comprises a first section and a second section, a gap is formed between the first section and the inner side wall of the valve body, the second section is hermetically connected with the inner side wall of the valve body, and a valve core through hole extends from the inner cavity of the valve core to the outer side wall of the first section;

a steel ball disposed between the first segment and the first joint inner interface;

and the spring is arranged in the valve body and pushes the valve core towards the first section so as to enable the first section to be propped against the limiting bulge.

Optionally, a first damping hole is arranged on a hydraulic pipeline between the back pressure valve and the port a of the first reversing valve, and a second damping hole is arranged on a hydraulic pipeline between the port B of the first reversing valve and the rod cavity of the oil cylinder.

Optionally, the oil tank further comprises a second reversing valve, the second reversing valve is provided with an A port, a B port, a P port and a T port, the A port of the second reversing valve is connected with a plug, the B port of the second reversing valve is connected with the P port of the first reversing valve, the P port of the second reversing valve is connected with the oil outlet of the fixed displacement pump, and the T port of the second reversing valve is connected with the inlet of the oil tank.

Optionally, the second reversing valve is a two-position four-way valve, and the first reversing valve is a three-position four-way solenoid valve.

Optionally, a first overflow valve is arranged between the port B of the second reversing valve and the port P of the first reversing valve.

Optionally, a check valve is arranged between the port P of the second reversing valve and the oil outlet of the fixed displacement pump.

Optionally, a second overflow valve is arranged between the oil outlet of the fixed displacement pump and the inlet of the one-way valve.

Through above-mentioned scheme, the control system who cuts fork lift carrier work platform that this application provided's beneficial effect lies in:

the control system of the working platform of the scissor lifting carrier comprises a first reversing valve, an oil cylinder, a back pressure valve, a direct current motor, a constant delivery pump and an oil tank; the first reversing valve is provided with an A port, a B port, a P port and a T port, the A port is connected with a rodless cavity of the oil cylinder, the B port is connected with a rod cavity of the oil cylinder, the P port is connected with an oil outlet of the constant delivery pump, the T port is connected with an inlet of the oil tank, the back pressure valve is arranged between the A port and the rodless cavity of the oil cylinder, and a driving shaft of the direct current motor is fixedly connected with a pump shaft of the constant delivery pump.

In the working process, when the oil cylinder descends, oil enters the back pressure valve from the rodless cavity of the oil cylinder and enters the first reversing valve through the back pressure valve, the back pressure valve improves the oil return back pressure of the oil cylinder and balances the change of the load, so that the oil cylinder cannot stall in the load descending process, and the descending stability of the oil cylinder is improved. In addition, the mode of the direct current motor and the constant delivery pump is adopted, the rotating speed range of the direct current motor has no dead zone, stepless speed regulation can be realized, and the stability of the oil cylinder during low-speed descending is ensured.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a control system of a working platform of a scissor lift truck according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a driving assembly according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram of a back pressure valve according to an embodiment of the present disclosure;

the reference signs are:

the device comprises an oil cylinder 1, a first overflow valve 2, a first reversing valve 3, a back pressure valve 4, a second reversing valve 5, a one-way valve 6, a dosing pump 7, a first filter 8, a second filter 9, a direct current motor 10, a second overflow valve 11, an oil tank 12, a plug 13, a Hall handle 14 and a driver 15;

the valve body 41, the valve body inner cavity 411 and the limiting bulge 412; a first joint 42, a first joint flow passage 421, a first joint inner port 422, and a first joint through hole 423; second joint 43, second joint flow passage 431; the valve core 44, the first section 441, the second section 442, the valve core inner cavity 443, the valve core through hole 444 and the installation groove 445; a steel ball 45; a spring 46; a damping 47; a seal 48.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Referring to fig. 1, the control system of the working platform of the scissors lifting truck provided by the present application includes an oil tank 12, an oil cylinder 1, a first direction valve 3, a second direction valve 5, a driving assembly, and a back pressure valve 4.

The oil cylinder 1 is provided with a rod cavity and a rodless cavity, the ascending of the oil cylinder 1 refers to the process of extending the piston, and the descending of the oil cylinder 1 refers to the process of retracting the piston.

The first reversing valve 3 can adopt a three-position four-way valve, and can be an electromagnetic valve and a hydraulic control valve. The first reversing valve 3 is provided with an A port, a B port, a P port and a T port, the A port of the first reversing valve 3 is connected with a rodless cavity of the oil cylinder 1, the B port of the first reversing valve 3 is connected with a rod cavity of the oil cylinder 1, the P port of the first reversing valve 3 is connected with an oil liquid outlet of the constant delivery pump 7, and the T port of the first reversing valve 3 is connected with an inlet of the oil tank 12.

The second reversing valve 5 can be a two-position four-way valve, can be an electromagnetic valve and can also be a hydraulic control valve, and the port P of the first reversing valve 3 is indirectly connected with an oil outlet of the fixed displacement pump 7 through the second reversing valve 5. Specifically, the second reversing valve 5 is provided with an A port, a B port, a P port and a T port, the A port of the second reversing valve 5 is connected with a plug 13, the B port of the second reversing valve 5 is connected with the P port of the first reversing valve 3, the P port of the second reversing valve 5 is connected with an oil outlet of the fixed displacement pump 7, and the T port of the second reversing valve 5 is connected with an inlet of the oil tank 12. In use, when the second reversing valve 5 is switched to the left valve position shown in fig. 1, the fixed displacement pump 7 drives oil to enter the port P of the first reversing valve 3 through the second reversing valve 5; when the second direction valve 5 is switched to the right valve position shown in fig. 1, the fixed displacement pump 7 cannot supply oil to the port P of the first direction valve 3.

The drive assembly comprises a dc motor 10 and a dosing pump 7. Wherein, the output shaft of direct current motor 10 passes through shaft coupling or other mechanical structure fixed connection with the pump shaft of constant delivery pump 7, and the output shaft of direct current motor 10 is rotatory the back, can drive the pump shaft synchronous revolution of constant delivery pump 7. An oil inlet of the fixed displacement pump 7 is connected with an outlet of the oil tank 12, and the fixed displacement pump 7 sucks oil from the oil tank 12 after being started. In practical applications, the fixed displacement pump 7 may be embodied as a gear pump.

Optionally, in an embodiment, the driving assembly further includes a hall handle 14, a controller and a driver 15, and the hall handle 14 includes a handle body and a hall sensor. When the brushless direct current motor is used, a user pushes and pulls the handle body of the Hall handle 14, the Hall sensor can generate an analog signal which is proportional to the moving distance of the handle body and outputs the analog signal to the controller, the controller converts the analog signal into PWM (pulse width modulation) pulses, meanwhile, the controller is electrically connected with the driver 15, the controller sends the PWM pulses to the driver 15, the driver 15 determines armature voltage signals according to the PWM pulses and controls the rotating speed of the direct current motor 10 according to the armature voltage. The rotating speed of the motor can be controlled through the amplitude of the push-pull handle body, so that the output flow of the constant delivery pump 7 is controlled, and the remote stepless speed regulation is realized.

The backpressure valve 4 is arranged on a hydraulic pipeline between the port A of the first reversing valve 3 and the rodless cavity of the oil cylinder 1 and used for providing oil return backpressure for the oil cylinder 1. The structure of the back pressure valve 4 can be referred to the prior art, and the present application provides a preferred structure of the back pressure valve 4 in the next embodiment.

Alternatively, in one embodiment, the back pressure valve 4 includes a valve body 41, a first joint 42, a second joint 43, a spool 44, a steel ball 45, a spring 46, a damper 47, and a packing 48.

The valve body 41 is a tubular structure, and has a valve body inner cavity 411 inside, and a limiting protrusion 412 is disposed on the side wall of the valve body inner cavity 411.

The first joint 42 is disposed at the first end of the valve body 41, and the first joint and the valve body 41 are fixedly connected, and during connection, the outer side wall of the first joint 42 may be in threaded connection with the side wall of the valve body inner cavity 411, or in a bolted connection, or fixed by other methods. A first joint flow passage 421 is provided in the first joint 42, one end of the first joint flow passage 421 is a P port, and the other end is a first joint inner port 422 communicated with the valve body inner cavity 411. The first joint through hole 423 penetrates through a side wall of the first joint 42, that is, the first joint through hole 423 extends from an outer side wall of the first joint 42 to the first joint flow passage 421, and the first joint through hole 423 communicates with the valve body inner chamber 411. The first joint 42 is connected directly to the rodless chamber of the cylinder 1 or indirectly through the oil pipe. The end of the first joint 42 where the port P is arranged can be threaded, so that the connection between the first joint 42 and the oil pipe or the rodless cavity of the oil cylinder 1 is realized.

The second joint 43 is disposed at the second end of the valve body 41, and the second joint and the valve body 41 are fixedly connected, and during connection, the outer side wall of the second joint 43 may be in threaded connection with the side wall of the valve body inner cavity 411, or in a bolted connection, or fixed by other methods. A second joint flow passage 431 is provided in the second joint 43, one end of the second joint flow passage 431 is an a port, and the other end is a second joint inner port communicated with the valve body inner cavity 411. The second joint 43 may be threaded at the end where the port a is located, so as to connect the second joint 43 to the hydraulic line.

The spool 44 has a tubular shape, and the spool 44 is provided inside the valve body 41, and the spool 44 has a spool cavity 443 inside. The valve body 44 is divided into two sections from one end to the other end, the two sections are a first section 441 and a second section 442, a gap is formed between the first section 441 and the inner side wall of the valve body 41, and the second section 442 is hermetically connected with the inner side wall of the valve body 41. The spool through hole 444 penetrates the sidewall of the spool 44, i.e., the spool through hole 444 extends from the spool inner cavity 443 to the outer sidewall of the first section 441.

The steel ball 45 is arranged between the first section 441 and the first joint inner interface 422. And the size of the steel ball 45 is matched with the size of the valve core inner cavity 443 of the end surface of the first section 441 and the size of the first joint inner interface 422, so that the steel ball 45 can block the valve core inner cavity 443 of the end surface of the first section 441 or block the first joint inner interface 422 when in different positions. In order to limit the position of the steel ball 45 during actual installation, it is preferable that the first segment 441 has an installation groove 445, and the steel ball 45 is installed in the installation groove 445. The inner diameter of the mounting groove 445 is larger than the outer diameter of the steel ball 45 so that the steel ball 45 can freely move in the mounting groove 445 under the effect of pressure.

The spring 46 is disposed inside the valve body 41, and the spring 46 pushes the valve element 44 toward the first section 441 by its elastic restoring force, so that the first section 441 is abutted against the limit protrusion 412. In actual installation, the spring 46 may be provided between the end surface of the valve body 41 and the end surface of the second joint 43; in order to limit the spring 46, it is preferable that a step surface facing the second joint 43 is provided in the valve body cavity 443, the spring 46 is provided in the valve body cavity 443, and one end of the spring 46 abuts against the step surface and the other end abuts against the second joint 43.

The damper 47 is arranged in the first joint flow passage 421, and the constant flow rate can be adjusted by changing the size of the damper 47. If the first joint flow passage 421 has a damping hole, the damper 47 can be omitted.

The gasket 48 is used for enhancing sealing, and during actual installation, a first joint boss located outside the valve body 41 may be provided on the first joint 42, and the gasket 48 is provided between the first joint boss and the end face of the valve body 41. A second joint boss located outside the valve body 41 may be provided on the second joint 43, and a seal gasket 48 may be provided between the second joint boss and the end surface of the valve body 41. The back pressure valve 4 may omit the gasket 48, and other parts or sealing methods may be used to ensure the sealing property of the internal hydraulic oil flow passage.

The back pressure valve 4 of the above-described structure operates as follows: in the first situation, during free flow, oil enters from the port A of the backpressure valve 4, the oil pushes the steel ball 45 to move through the second joint flow passage 431 and the valve core inner cavity 443, and the steel ball 45 blocks the first joint inner port 422; meanwhile, the oil passes through the second joint flow passage 431, the spool inner cavity 443, the valve body inner cavity 411, the first joint through hole 423, and the first joint flow passage 421, and finally flows out from the port P of the back pressure valve 4. In the second case, if oil enters from port P of the back pressure valve 4, the oil pushes the steel ball 45, the steel ball 45 pushes the spool 44 to move toward the second joint 43, and the spring 46 pushes the spool 44 to move toward the first joint 42. If the thrust of the oil on the valve core 44 does not reach the thrust of the spring 46, the valve core 44 abuts against the limiting protrusion 412, the steel ball 45 blocks the inner cavity 443 of the valve core, so that the valve core 44 is closed, the oil does not circulate, and the pressure maintaining effect is achieved. In the third case, if oil enters from the port P of the back pressure valve 4 and the thrust of the spool 44 of the oil is greater than the thrust of the spring 46, the spring 46 is compressed at this time, the spool 44 moves to the second joint 43 under the control of the oil, and the oil passes through the first joint flow passage 421, the valve body inner chamber 411, the spool through hole 444, the spool inner chamber 443, the second joint flow passage 431, and finally flows out from the port a of the back pressure valve 4.

Optionally, a check valve may be disposed on the hydraulic pipeline to ensure one-way flow of oil. For example, a check valve 6 may be provided between the port P of the second direction valve 5 and the oil outlet of the fixed displacement pump 7.

Optionally, an overflow valve may be disposed on the hydraulic line to adjust the pressure of the hydraulic line. For example, the first relief valve 2 may be provided between the port B of the second direction valve 5 and the port P of the first direction valve 3. For another example, a second relief valve 11 may be provided between the oil outlet of the fixed displacement pump 7 and the inlet of the check valve 6.

Optionally, a damping hole may be provided on the hydraulic line to perform the pressure regulating and buffering functions, for example, a first damping hole may be provided on the hydraulic line between the back pressure valve 4 and the port a of the first direction valve 3. For another example, a second orifice may be provided in the hydraulic line between the port B of the first direction valve 3 and the rod chamber of the cylinder 1. For another example, a third orifice may be provided in the hydraulic line between the T port of the second direction valve 5 and the inlet port of the tank 12.

Optionally, a filter may be disposed on the hydraulic line to ensure cleanliness of the oil. For example, a first filter 8 may be provided on the hydraulic line between the oil inlet of the fixed displacement pump 7 and the outlet of the tank 12. For another example, a second filter 9 may be provided at the outlet of the second relief valve 11.

The working process of the control system of the scissor lifting carrier working platform with the structure is as follows:

the driving assembly provides a power source and controls the output value of the flow of the fixed displacement pump 7 by adjusting the rotating speed of the direct current motor 10. When the lifting platform rises, the direct current motor 10 is started to drive the fixed displacement pump 7 to output flow, the YV1 of the first reversing valve 3 is electrified, oil enters a rodless cavity of the oil cylinder 1 through the back pressure valve 4, and a piston rod is pushed to extend out; when the lifting platform descends, the starting motor drives the gear pump to output hydraulic flow, the YV2 of the first reversing valve 3 is electrified, oil enters the rod cavity of the oil cylinder 1, the oil in the rodless cavity of the oil cylinder 1 flows back to the oil tank 12 through the back pressure valve 4, and the piston rod retracts.

It can be seen from the above embodiment that the control system of the scissor lifting carrier working platform provided by the application has the beneficial effects that:

the stepless speed regulation is realized by regulating the rotating speed of the direct current motor 10, smaller flow can be output, a hydraulic speed regulating valve is not required to be added, and the price is low. By adding the back pressure valve 4, the oil return back pressure is improved, the weight of the working platform and the load of the working platform is balanced, and the descending stability of the oil cylinder 1 is improved. The problem of the shake of scissors fork lift carrier when the low-speed descends to and the stall problem in the loading decline in-process is solved.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The control system of the working platform of the scissor lifting truck provided by the application is described in detail above. The principles and embodiments of the present application are explained herein using specific examples, which are provided only to help understand the method and the core idea of the present application. It should be noted that, for those skilled in the art, it is possible to make several improvements and modifications to the present application without departing from the principle of the present application, and such improvements and modifications also fall within the scope of the claims of the present application.