Why Are Early Return Systems Important?
Early return systems return the ejector assembly back before the mold completely closes. They are employed when ejector pins or other moving components, such as slides, interfere with normal closure. Besides the early return function, these systems must also lock the ejector assembly firmly in place. This must be done to prevent expensive mold damage and repair. A variety of return methods can be used such as mechanical, springs, pneumatics, or hydraulics.
Early return systems can be employed inside or outside the mold base. The outside method is the more common method because of space requirements inside the mold. The presence of water lines may necessitate the use of an internal early return system.
Internal Early Return Systems – Application
An internal system for early ejector assembly return is shown here. It is a unique design that permits simple, low-cost installation saving time and money. This system does not take up valuable inside mold space nor outside space needed for water lines and manifolds.
Internal Early Return Systems – Actuation
The fully opened mold shown has the ejector assembly in its eject position. As the ejector half of the mold closes the long leader pins make contact with the closed cam-fingers early in the mold close sequence. This interference forces the ejector assembly to return until it hits the stop buttons. At this location the cam-fingers can be forced open into a recessed area in the bushing. This allows the leader pins to pass through the cam fingers and the mold to completely close.
External Early Return Systems – Application
A Toggle Lock is an early return device used to positively return the ejector assembly before the mold completely closes. It is employed when ejector pins or slides interfere with normal mold closure. The external mounting allows more space for cavities, slides and other mold components. The Toggle-Lock system is available in three styles to suit a broad variety of applications. Each style corresponds to a specific mold base requirement.
External Early Return Systems – Actuation
The mold shown, when fully open, has the ejector assembly in its eject position. As the ejector half of the mold closes, the long levers contact the arms, forcing the ejector assembly to return. This must be done before the cam pins contact the slides. If not, the slides would move in and crash into the ejector pins. As the mold continues to close the levers keep the ejector assembly back, while the cam pins move the slide blocks into the mold closed position. Note: The actuation animation has been simplified for clarity.
Early Return Systems Summary
The purpose of early return systems is to return the ejector assembly completely back before the mold closes. They are used when ejector pins or other moving components interfere with normal closure of the mold base. This is done to prevent expensive damage and mold repair. These systems can be employed internally or externally. The internal early return system is called the Early Ejector Return Assembly and the external system is called the Toggle-Lock.
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