Automated mechanism to fold and unfold lift truck forks and related process

A fork lift mechanism, comprising:

• a mast;
• a carriage slidably supported by the mast, the carriage including a backing plate;
• a plurality of forks pivotally supported by the carriage, each including a fork tine, a fork back extending generally perpendicularly to the fork tine, and a mounting sleeve between the fork tine and the fork back, wherein a fork mounting shaft supported by the carriage extends through each mounting sleeve to permit pivotal movement of the fork about the mounting shaft;
• a plurality of latches corresponding to the plurality of forks and supported by the mast, each latch being pivotable between a fork back engaging position and a neutral position;
• means for biasing the latches toward their neutral position;
• and
• means for selectively moving the latches between the engaging and the neutral positions;
• wherein under normal operating conditions the fork backs engage the carriage backing plate so that the fork tines extend generally perpendicularly outwardly from the carriage as the carriage is moved relative to the mast, but when the latches are caused to engage the fork backs, the fork backs are pulled away from the backing plate as the carriage is raised to cause the fork tines to pivot and lie generally parallel to the carriage.

A process for folding and unfolding a lift truck fork in response to movement of a carriage relative to a supporting mast, comprising the steps of:

• pivotally supporting the lift truck fork on the carriage such that under normal conditions a fork tine of the lift truck fork extends outwardly generally perpendicularly from the carriage in an unfolded position;
• providing a latch connected to the mast and capable of selectively engaging the lift truck fork;
• causing the latch to engage the lift truck fork when the carriage is at or near the bottom of the mast;
• raising the carriage to cause the fork tine to pivot until it is caused to lie generally parallel to the carriage in a folded position;
• and
• subsequently lowering the carriage to cause the fork tine to pivot back to its unfolded position wherein it extends generally perpendicularly from the carriage.