Compact hydraulic drive for die closing unit of injection molding machine
US4380427A · kind A · utility
Inventor
Key dates
| Filing date | Nov 24, 1981 |
| Grant date | Apr 19, 1983 |
| Priority date | — |
| Expiry date | Nov 24, 2001 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2045/6785
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A hydraulic actuator assembly for a push-type die closing unit of an injection molding machine capable of producing rapid die opening and closing movements with a small volume of pressurized fluid and an elevated die closing pressure in the closed die position, the assembly comprising a central power cylinder with a selectively bypassable power piston and two parallel, diametrally oppositely arranged single-acting travel cylinders. The low-pressure space on the forward side of the power piston is open to the pressure spaces of the two travel cylinders, and the total effective area of these pressure spaces is larger, by a relatively small amount, than the area of the high-pressure space to the rear of the power piston, said small amount determining the fluid volume necessary for the opening travel. A stationary plunger cooperates with a central bore in the rear portion of the power piston rod to produce a small pressure space for the closing travel. An elevated die closing pressure is obtained by pressurizing the high-pressure space of the power piston and the plunger pressure space, with the power piston bypass closed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.