Prensa hidráulica de tres vigas y cuatro columnas
1.Máquina de corte de cuero hidráulico, la composición básica de la máquina de prensa hidráulica de cuatro columnas y tres vigas

Hydraulic leather cutting machine,The basic composition of the three-beam four-column hydraulic press machine is understood through this figure. The four-column hydraulic press machine converts mechanical energy into pressure energy through a hydraulic system through a hydraulic pump, and uses the Pascal principio to transfer the energy required for work. Control cylinders through various control valves and hydraulic lines. Furthermore, the back-and-forth working movement of the movable beam driven by the hydraulic cilindro is controlled to provide the pressure required for work. After the pressing of the required workpiece is completed, the forging formed workpiece is ejected by the ejection cylinder.
2.Analysis of action sequence of four-column hydraulic press machine

Figure-2 Four-column hydraulic press machine control sequence diagram
The operating sequence of the hydraulic cylinder is controlled by the hydraulic system and the electrical system in the hydraulic press machine.

Figure 3 (a) shows the operation of the master cylinder, and Figure 3 (b) shows the working diagram of the ejector cylinder.
3.Comparison of hydraulic cylinders
(1) Plunger type hydraulic cylinder
The schematic diagram of the plunger type hydraulic cylinder is shown in Figure 4 below, and its schematic diagram is shown in Figure 5 below.

As shown in the figure above, it is mainly composed of cylinder barrel, hydraulic piston rod, plunger, seal ring, guide ring and other pieces. The flange structure on the cylinder block is used for fixing in the upper beam.
Features: The plunger-type oil cylinder does not need to be machined, or even needs to be machined. It is easy to manufacture and simple to maintain. It is widely used in hydraulic presses machine, but the disadvantage is that it can only act in one direction, and the reverse movement needs to be achieved by a return cylinder.
(2) Piston cylinder
The structure of the piston hydraulic cylinder is shown in Figure 6 below.

Features: It can realize the left and right movement of the hydraulic cylinder, which is equivalent to the combination of two plunger hydraulic cylinders. And this structure of the hydraulic cylinder is widely used in small and medium hydraulic press machines. Its structure is relatively simple and easy to manufacture.
(3) Compound oil cylinder
A compound oil cylinder combining a piston type hydraulic cylinder and a plunger type hydraulic cylinder as basic forms.