Sheet folding apparatus and method

Claim 3

The method as defined in claim 1, and causing said first and second tucker blades to swing back and forth between the first and second grippers on arcuate paths coincident with arcs on which the grippers are disposed.

Claim 4

The method as defined in claim 2, and causing the first and second tucker blades to alternately rise and fall during their arcuate movement toward and away from the first and second grippers.

Claim 5

The method as defined in claim 1, and causing the first and second grippers to resiliently and releasably grip the folded sheet.

Claim 6

A sheet folding apparatus comprising in combination means to receive sheets individually and to deliver them to a substantially vertical hanging position where each sheet is lightly held frictionally, a pair of opposed grippers on opposite sides of each hanging sheet, each gripper consisting of a pair of opposed gripper plates and spring means resiliently urging the plates into yielding clamping contact, a swingable tucker unit between said grippers including a pair of opposed tucker blades each adapted to enter between the opposed gripper plates of one of said grippers to produce a fold in each sheet, one tucker blade disposed on each side of each hanging sheet, linkage means connected with said tucker unit to swing the unit in opposite directions relative to the sheet and between the opposed grippers so that each tucker blade in turn engages one side of each sheet and forces the sheet between the opposed tucker blades of the opposing gripper to form a fold in said sheet, said linkage means producing movement of the other previously inactive tucker blade with said sheet between the opposed gripper plates of the other previously inactive gripper to form another fold in said sheet and in so doing tensioning the sheet and withdrawing it from between the gripper plates of the gripper in which the sheet was previously folded, and a connection between said tucker blades causing them to rise and fall relativEly and relative to the grippers during swinging movement of the tucker unit.

Claim 7

A sheet folding apparatus comprising in combination means to receive sheets individually and to deliver them to a substantially vertical hanging position where each sheet is lightly held frictionally, a pair of opposed grippers on opposite sides of each hanging sheet, each gripper consisting of a pair of opposed gripper plates and spring means resiliently urging the plates into yielding clamping contact, a swingable tucker unit between said grippers including a pair of opposed tucker blades each adapted to enter between the opposed gripper plates of one of said grippers to produce a fold in each sheet, one tucker blade disposed on each side of each hanging sheet, linkage means connected with said tucker unit to swing the unit in opposite directions relative to the sheet and between the opposed grippers so that each tucker blade in turn engages one side of each sheet and forces the sheet between the opposed tucker blades of the opposing gripper to form a fold in said sheet, said linkage means producing movement of the other previously inactive tucker blade with said sheet between the opposed gripper plates of the other previously inactive gripper to form another fold in said sheet and in so doing tensioning the sheet and withdrawing it from between the gripper plates of the gripper in which the sheet was previously folded, and a connection between said tucker blades causing them to rise and fall relativEly and relative to the grippers during swinging movement of the tucker unit.

Claim 8

The structure as defined in claim 5, and said swinging tucker unit comprising a pair of crossing individually pivoted arms, said opposed tucker blades carried by the lower ends of the arms, and said connection comprising a link pivotally interconnecting the arms and having a pivotal connection between the arms with said linkage means.

Claim 9

The structure as defined in claim 6, and said linkage means including a rotary member having a single crank element.

Claim 10

The structure as defined in claim 7, and said opposed grippers including gripper arms having their upper ends pivoted to the same elements which pivotally support said arms of the tucker unit, and means to adjust the lower ends of the gripper arms toward and from each other on an arc around said pivot elements.

Claim 11

The structure as defined in claim 8, and a pair of gripper plates on the lower end portion of each gripper arm with one plate of each pair resiliently urged toward the other plate.

Claim 12

A sheet folding apparatus comprising a support for a stack of sheets to be folded, a power-operated feed roll on the support in advance of the stack and adapted to engage and feed individual sheets fed manually from the stack toward the feed roll, a cooperating presser roll bearing on the feed roll and being movably supported, means forming a substantially vertical guide passage for each sheet below the feed roll, an element mounted to move with the presser roll and adapted to frictionally engage each sheet in the vertical guide passage and support the sheet when the presser roll is moved away from the feed roll to interrupt the positive feeding of the sheet, a sensing element projecting into said guide passage and responding to engagement with the leading and trailing edges of each sheet to initiate movement of the presser roll away from the feed roll and to start a sheet feeding cycle after a preset time delay interval and to terminate the folding cycle and again move the presser roll into engagement with the feed roll, a pair of opposed relatively fixed resilient gripper devices arranged on opposite sides of each sheet in the vertical guide passage, a pair of cooperating opposed tucker blades swingably mounted between the gripper devices and arranged on opposite sides of each sheet in said vertical guide passage, power driven linkage means connected with the tucker blades to oscillate the same between the gripper devices and to cause rising and falling of the tucker blades alternately as they oscillate between the gripper devices, whereby one tucker blade engages one side of each sheet and forces the sheet into one gripper device to produce a first fold in the sheet, followed by the other tucker blade engaging the opposite side of each sheet and forcing the sheet into the second gripper device to produce a second fold in the sheet and in so doing pulling the sheet out of the first gripper device.

Claim 13

A sheet folding apparatus comprising a support for a stack of sheets to be folded, a power-operated feed roll on the support in advance of the stack and adapted to engage and feed individual sheets fed manually from the stack toward the feed roll, a cooperating presser roll bearing on the feed roll and being movably supported, means forming a substantially vertical guide passage for each sheet below the feed roll, an element mounted to move with the presser roll and adapted to frictionally engage each sheet in the vertical guide passage and support the sheet when the presser roll is moved away from the feed roll to interrupt the positive feeding of the sheet, a sensing element projecting into said guide passage and responding to engagement with the leading and trailing edges of each sheet to initiate movement of the presser roll away from the feed roll and to start a sheet feeding cycle after a preset time delay interval and to terminate the folding cycle and again move the presser roll into engagement with the feed roll, a pair of opposed relatively fixed resilient gripper devices arranged on opposite sides of each sheet in the vertical guide passage, a pair of cooperating opposed tucker blades swingably mounted between the gripper devices and arranged on opposite sides of each sheet in said vertical guide passage, power driven linkage means connected with the tucker blades to oscillate the same between the gripper devices and to cause rising and falling of the tucker blades alternately as they oscillate between the gripper devices, whereby one tucker blade engages one side of each sheet and forces the sheet into one gripper device to produce a first fold in the sheet, followed by the other tucker blade engaging the opposite side of each sheet and forcing the sheet into the second gripper device to produce a second fold in the sheet and in so doing pulling the sheet out of the first gripper device.

Claim 14

The structure as defined in claim 10, and a power-operated device activated by the sensing element to substantially simultaneously shift the presser roll away from the rotating feed roll and to move said element into frictional engagement with the sheet in said guide passage and to activate said cooperating tucker and gripper devices for a predetermined cycle.

Claim 15

The structure as defined in claim 11, and said power-operated device including a solenoid.