Lifting hydraulic control system

[0018] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings:

[0019] As shown in the figure: a lifting device, including a lifting mechanism and a hydraulic control system, the lifting mechanism includes two sets of lifting units, the lifting unit includes a lower support plate 6, an upper lifting platform 7 and Four support arms, the support arm consists of two parallel support rods, the ends and the middle of the two support rods are fixedly connected with cross bars;

[0020] A lower rail 9'is provided on the top surface of the lower support plate 6, and an upper rail 9 is provided on the bottom surface of the upper lifting platform 7,

[0021] A position switch 10 is provided on the upper rail 9 and the lower rail 9', and the position of the position switch 10 on the rail is adjustable; the first support arm 1 and the second support arm 2 are arranged in an X-shaped cross, The intermediate position of the first support arm 1 and the second support arm 2 is hinged by a pin, the bottom end of the first support arm 1 is hinged to one end of the lower support plate 6, and the bottom end of the second support arm 2 is provided with a lower roller 8' , The lower roller 8'slides on the lower rail 9'; the bottom end of the third support arm 3 is hinged to the top end of the second support arm 2, and the bottom end of the fourth support arm 4 is hinged to the top end of the first support arm 1. , The third support arm 3 and the fourth support arm 4 are arranged crosswise in an X shape, the middle position of the third support arm 3 and the fourth support arm 4 are hinged by a pin, and the top end of the third support arm 3 is provided with an upper roller 8. The upper roller 8 is in a rolling state on the upper rail 9. The top end of the fourth support arm 4 is hinged to one end of the bottom of the upper lifting platform 7; the fixed end of the hydraulic cylinder 5 is hinged to the second support arm 2 In the lower section, the extension end of the hydraulic cylinder 5 is hinged to the lower section of the third support arm 3. The hydraulic cylinders 5 of the two lifting units are both connected to the hydraulic control system.

[0022] The hydraulic control unit includes an oil tank 11, a hydraulic pump 12, and a hydraulic control circuit. The input end of the hydraulic pump 12 is connected to the oil tank 11 through a pipeline, and the output end of the hydraulic pump 12 is connected to the P port of the three-position four-way valve 13. The T port of the four-position valve 13 is connected to the oil tank 11 through a pipeline, the A port of the three-position four-way valve 13 is connected to the input end of the balance valve 14, and the two output ends of the balance valve 14 are each connected to a hydraulic control valve One input end of 15, the B port of the three-position four-way valve 13 is connected to the other input end of the hydraulic control valve 15 in two ways, and the output end of the hydraulic control valve 15 is respectively connected to the input of the corresponding hydraulic cylinder 5. The pipeline between the hydraulic control valve 15 and the input end of the hydraulic cylinder 5 is provided with a solenoid valve reversing valve 16 branch, the input end of the solenoid reversing valve 16 is connected to the input end of the hydraulic cylinder 5, and the solenoid valve The two output ends of the reversing valve 16 are respectively connected to the oil tank 11 via pipelines; the output end of the hydraulic pump 12 and the three-position four-way valve 13 are connected in parallel with an overflow valve 17, and the input end of the overflow valve is connected to the hydraulic The output end of the pump 12, one output end of the overflow valve 17 is connected to the oil tank, and the other output end of the overflow valve 17 is connected to a pressure gauge; the three-position four-way valve 13 has a throttle valve 18 branch at port B The throttle valve branch is connected to the oil tank 11, and the throttle valve 18 is an adjustable throttle valve.

[0023] The hydraulic pump 12, the three-position four-way valve 13, the electromagnetic reversing valve 16 and the position switch 10 are connected to the control circuit 19.

[0024] The control principle of the hydraulic control system is: the hydraulic pump 12 outputs hydraulic oil from the oil tank 11, the hydraulic oil enters the balance valve 14 through the three-position four-way valve 13, and the balance valve 14 divides the oil supply into two ways, and the hydraulic oil enters the hydraulic control valve 15. The channel of the hydraulic control valve 15 is opened inside the top, and the two oils are balanced into the hydraulic cylinders 5 of the two lifting units, and the hydraulic cylinders 5 drive the lifting units to lift. When the lifting is overloaded, the delivery pressure of the hydraulic pump exceeds the range set by the relief valve 17, and the hydraulic oil spills from the relief valve 17 parallel to the output end of the hydraulic pump 12 to the tank 11; when the lifting platform needs to be lowered, The hydraulic pump 12 delivers oil, and the hydraulic oil enters the other input end of the two-way hydraulic control valve 15 in two ways through the B port of the three-position four-way valve and opens the channel of the hydraulic control valve. The oil return in the hydraulic cylinder 5 is hydraulic The control valve 15 returns to the original path after being balanced by the balance valve 14 and then enters the three-position four-way valve 13 and returns to the oil tank from the T port of the three-position four-way valve 13; when the hydraulic pump 12 is damaged, the oil return in the hydraulic cylinder 5 is from the solenoid One oil return line of the reversing valve 16 directly returns oil to the oil tank 11. When the oil return on both sides is not equal, the other oil return line of the electromagnetic reversing valve 16 can be manually adjusted for oil return compensation to ensure oil return balance.