Paper stacker

An elevator mechanism for use to support and vary the height of a moveable floor which is to support paper sheets received from a printer or copier, the elevator mechanism comprising:

• a base having a top surface defining four openings;
• four close-coiled spring supports located in the openings and having upright portions above the openings, terminating an outer ends for engagement under the floor, bent portions immediately below the openings, and horizontal portions contained in the base and terminating at inner ends, the bent portions forming transitions between the respective horizontal and upright portions of the supports;
• and
• drive means attached to the base and in engagement with the supports at said inner ends and operable to push the supports outwardly to increase the lengths of the upright portions, and to pull the supports to decrease the lengths of the supports whereby the elevation of the floor can be changed.

A paper guide mechanism for use in deflecting selected paper sheets sideways as they travel into a hopper to build up a stack of paper sheets in which the selected sheets are staggered with reference to the remaining sheets, the mechanism comprising:

• a deflector rotatable about a first axis;
• drive means operable to rotate the deflector;
• and
• suspension means supporting the deflector about a second axis at right angles to said first axis with the deflector biassed to fall downwards about the second axis to engage the paper sheets so that in operation the deflector drives the selected sheets as they engage the deflector as they travel into the hopper.

A paper stacker for use at the output from a sheet printer or copier to collect the sheets, the stacker comprising:

• a base
• an elevator mechanism attached to the base;
• a hopper supported by the base and having a movable floor which receives the sheets of paper travelling horizontally to build a stack on the floor of the hopper, the floor being supported by the elevator mechanism for movement vertically in the hopper between upper and lower positions;
• sensor means positioned to sense when the stack of paper building on the floor of the hopper reaches a predetermined level;
• and
• drive means responsive to the sensor means to move the elevator mechanism so that the floor moves downwards to make room for more sheets to be fed onto the top of the stack,
• the elevator mechanism comprising four retractable supports of close coiled springs, each of the springs having an upright portion exposed above the base and terminating in supporting contact with the moveable floor, a bent portion forming a transition from vertical to horizontal, and a horizontal portion contained in the base;
• guide means in the base maintaining the horizontal portions in position and bends in said bent portions;
• and moving means contained in the base and in engagement with inner ends of the springs to move the supports horizontally inside the base thereby changing the height of the moveable floor.