US 4,301,100 AGranted

Method and apparatus for setting a clamping load

AssigneePackage Machinery Company

InventorRobert E. Farrell

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Abstract

The clamping preload in a molding machine or the like is set by adjusting the length of tie bars which support two die plates for opening and closing movement and a thrust plate. A clamping mechanism of given stroke is positioned between the thrust plate and one of the disc plates, and operates to close the die plates at one limit of the clamping stroke. With the clamping mechanism set at its limit and the tie bars set to establish a slight spacing between the die plates, the length of the tie bars is adjusted by means of a drive motor until the die plates are in contact without substantial preload. The clamping mechanism then opens the die plates and the drive motor is further energized to adjust the length of the tie bars and bring the die plates closer to one another by an amount corresponding to a preselected preload. The adjustment is measured from a high ratio mechanical drive connecting the drive motor to the adjustable tie bars, and the measured adjustment is compared with a desired adjustment corresponding to the preselected preload to deenergize the drive motor when the desired adjustment is reached.

Claims7

Dependent claims

A method of setting the preload between two die plates that are moved between opened and closed positions by means of a clamping mechanism of given stroke comprising:

providing an adjustable linkage between the clamping mechanism of given stroke and one of the die plates opened and closed by the clamping mechanism to adjust the stress in the linkage and the corresponding preload between the plates in the closed position at one limit of the clamping mechanism stroke;
adjusting the linkage between the clamping mechanism and said one of the die plates to a first length which separates the two die plates when the clamping mechanism is at said one limit of the stroke;
with the clamping mechanism at said one limit of the stroke, adjusting the linkage between the clamping mechanism and said one of the die plates from the first length to a second length which brings the two die plates into a known position relative to one another;
and then
moving the clamping mechanism from said one limit of the given stroke toward the other limit to establish a separation between the die plates with the adjustable linkage at the second length;
and then
changing the length of the adjustable linkage by a measured amount from the second length to a third length which preloads the die plates in the closed position by a corresponding amount when the clamping mechanism is subsequently returned to said one limit of the clamping mechanism stroke.

4 more elements

Dependencies are inferred from the claim text.