Drive hydraulic cylinder

Molds with core pullers are used for very deep lateral undercuts mostly driven by hydraulic means rather than using pneumatic drive. Hydraulic cylinders are also used for bigger splits. In each case a mechanical locking against the separating forces is necessary. 

They are designed to provide a flexible link between a power supply, such as a hydraulic cylinder, and another machine component. Leaf chains do not have any rollers or other sprocket-engaging device. They are designed with connector links located at each end of the chain that can be used to connect the drive and driven machine components. 

Fig. 4.1-35. Diaphragm compressor (HOFER). a, Diaphragm b, Gas space c, Discharge valve d, Suction valve e, Diaphragm cover f, Perforated plate g, Hydraulic cylinder h, Oil overflow valve i, Oil return j, Cylinder cooling k, Check valve 1, Crank drive m, Cooling-water in/out n, Oil-cooling coil o, Oil chamber p, Oil injection (leakage compensation) q, Compensation pump r, Check valve s, Oil supply.

By using hydraulic cylinders for compaction in punch-and-die presses, which den-sify particulate materials in a totally enclosed, diminishing volume, in addition to being able to modify punch speed, it is also easy to maintain the highest pressure during an (adjustable) dwell time. Similar speed and dwell time adjustments are also possible with adjustable cam drives in rotary tabletting machines (Section 6.2.2 [B.48, B.97]). 

Servo press with ball screw drive system This press system is shown in Fig. 6b and resembles more the hydraulic drive system, if the hydraulic cylinders are replaced by ball screws with a motor for each pressure point, alternatively by one motor and a gear system to move the thread spindles synchronously. 

The adhesive is packaged in a composite foil bag within a pail of 280 mm diameter and 380 mm height. After insertion of the composite foil bag into express tube, a hydraulic cylinder drives the adhesive into the heating chamber and then to the feeding pump. Heated hoses lead the molten adhesive to the nozzle where a volume-dosing unit can be attached. 

Pneumatic and hydraulic drives provide independent control, but a greater amount of space is needed to install and cool the cylinder. In manifold nozzles the cylinder is usually set into the mould clamping plate, and in some designs it is made as part of the plate. The hydraulic cylinder temperature may not exceed 80-100 °C, so at high processing temperatures the clamping plate must be cooled. There are also systems with an extra plate accommodating a complete drive system, e.g., Mold-Masters systems. 

In the case of the nozzle shown in Figure 4.41b, the hydraulic cylinder is installed with an articulation, and the drive is transmitted to the pin via a lever with a toothed segment and a rack. 

Nozzles shown in Figure 4.41c are equipped with a 4 MPa hydraulic cylinder and a cylinder is a part of the mould plate. The drive is transmitted to the pin via an articulated lever. 

Figure 4.42 Central nozzle with pin drive via hydraulic cylinder lever...

For moulds with injection points situated in a line, nozzles with a pin drive by a single hydraulic cylinder located at the side of the mould have been developed (see Figure 4.44). 

Fig. 44 illustrates a billet-fed lead cable press. The up-stroking design, as shown in Fig. 18, is the most suitable type, because the ram must be traversed to permit of charging the billet, for which purpose a small hydraulic cylinder with plunger and guide-frame is fixed on the face of the upper platen. With a down-stroking press, this drive unit would have to be mounted on the movable crosshead which would call for connection by hoses or telescopic tubes. 

Oil hydraulics has become firmly established as the drive system for the vast majority of injection molding machines and until recently was almost unchallenged as the power source. Put at its simplest, the injection molding machine contains a reservoir of hydraulic oil which is pumped by an electrically-driven pump at high pressure, typically at up to 14 MPa, to actuating cylinders and motors. High and low pressure linear movements are performed by hydraulic cylinders, and rotary movements for screw drive and other purposes are achieved by hydraulic motors. Hybrid machines, in which the screw is driven by electric motor while the linear movements remain hydraulically powered, are not uneommon. 

Hydraulic cylinder for sealing nozzle, 4. Seal from the drive side,... 

Dual drive magnetic clutch Two or four cylinder open compressor Hydraulic motor... 

Air from a cylinder at pressures up to about 10 bar (150 psi) is applied to a gas piston that has a relatively large surface area. The gas piston is attached to a hydraulic piston that has a smaller surface area. The pressure applied to the liquid = gas pressure x area of gas piston/area of hydraulic piston. With 10 bar inlet pressure and a 50 1 area ratio, the hydraulic pressure obtained is 500 bar (7500 psi). On the drive stroke, the outlet valve on the pump head is open to the column and the inlet valve closed to the mobile phase reservoir. At the end of the drive stroke, the air in the chamber is vented and air enters on the other side of the gas piston to start the return stroke. On the return stroke the outlet valve closes, the inlet valve opens and the pump head refills with mobile phase. The pump can be started and stopped by operation of a valve fitted between the cylinder regulator and the pump. 

Figure 7 shows the oven in forward position. All process parts in contact with the chemicals exposed to the hot environment are manufactured from stainless steel. The gear drives for the tank agitatiors and the hydraulic actuators for the mixing head and for the metering cylinders are arranged outside of the enclosure in ambient environment. The drive parts are coupled to the hot parts by insulated connections for preventing heat transfer. 

The hydraulic motor drive was a piston-type, nine-cylinder, fixed-stroke imit and provided a rated 40 hp at 6000 rpm with 25-gpm oil at 3000 psi. This accommodated a high-output pump performance of 100 psi shutoff head at 8500 rpm, and 1510 gpm at... 

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