Signature stacker employing swingable intercept means driven in a non-linear fashion

4,037,525

05/600,491

July 30, 1975

A signature stacker having an infeed section for receiving a continuous stream of signatures arranged in overlapping fashion to form either compensated or uncompensated bundles having a predetermined and precise number of signatures. Counter means in the infeed section counts each signature in the stream to generate a signal upon accumulation of a predetermined count to activate a retractable stop means which enables a preloaded swingable intercept blade to be abruptly urged into the path of the signature stream which is passing from the infeed conveyor towards a reciprocating blade assembly. The signatures for the bundle being completed are deposited by a downwardly moving reciprocating stacking blade assembly upon the bundle holding bucket of an outfeed assembly, said intercept blade passing through the intercept region for a period sufficient to enable the stacking blade assembly to move downwardly to deposit a completed bundle (or bundle portion) and to return to the uppermost position in readiness for receiving the next group of signatures.

Sjogren, Christer A. (Miami, FL); Backman, Ralph H. (Taby, SW)

EDS, Inc. (Hialeah Gardens, FL)

We claim

1. A stacker for forming bundles containing a preselected number of signatures from an incoming signature stream delivered to the stacker with the signatures arranged in overlapping fashion, said stacker comprising

infeed conveyor means for receiving said signature stream;

an outfeed location means;

swingable blade means including a blade assembly having tips movable across the downstream end of said infeed conveyor means to intercept said stream;

reciprocating stop means for normally preventing said tips from moving in the path of the signature stream as the signatures leave the infeed conveyor means when said stop means is in an extended position;

preloading means for biasing said blade means in a first direction and against said stop means;

means positioned in said infeed conveyor means for counting said signatures to generate a trigger signal upon reaching a count representative of the desired bundle size;

reciprocating means positioned beneath said blade means for stacking signatures delivered from said conveyor means and blade means to form a bundle when in the collection position and dropping the formed bundle upon said outfeed location means positioned therebeneath when in the withdrawn position;

drive means responsive to said trigger signal to move said stop means to a withdrawn position displaced away from said blade tips into said stream for temporarily collecting a quantity of signatures on said blade means for a period sufficient to permit the said receiving means to complete its operation;

means for thereafter rapidly rotating said blade assembly from a rest condition through substantially one full revolution and back to said rest condition to deposit the signatures temporarily held thereon to said receiving means and return said blade tips to the position above said stop means and being urged against the stop means by said preloading means in readiness for the next intercept operation;

said rotating means including means for moving said assembly at a faster rate during the intermediate portion of each revolution to move the blades from beneath the signatures deposited thereon so that the signatures undergo free-fall to be deposited upon said reciprocating means.

2. The stacker of claim 1, wherein said drive means further includes means for moving said stop means to the extended position before said blade means completes one revolution to thereby prevent said blade means tips from moving into said stream until the next trigger signal is received.

3. The stacker of claim 1, wherein said infeed conveyor means further comprises a pair of cooperating rollers defining the downstream end of said infeed conveyor means;

means for swingably mounting said pair of rollers;

means for rotating said rollers to cause said rollers to urge signatures passing therebetween towards said stacking means;

means coupled to said swingable mounting means for lifting said pair of rollers upwardly when said stop means is in the withdrawn position to increase the gap between said blade tips and said stop means to facilitate the passage of signatures passing beneath said stop means and being temporarily collected upon said blade means.

4. The stacker of claim 3, wherein said swingable mounting means further comprises first and second pivotally mounted arms each adapted to swing about a stationary pivot point;

each of said rollers being rotatably mounted between the free swingable ends of an associated pair of arms;

air cylinder means mounted between said first and second pairs of swingable arms for urging said rollers towards one another to squeeze signatures passing therebetween, the urging force exerted upon said rollers being substantially constant even in the case where the spacing between the first and second pairs of arms changes with changes in thickness of the signature stream.

5. The stacker of claim 4 wherein said downstream infeed rollers each have a substantially V-shaped configuration for imparting a similar shape to signatures passing therebetween to stiffen the signatures and thereby facilitate handling and stacking of the signatures.

6. The stacker of claim 1 wherein said rotating means is comprised of motor means;

single revolution clutch means having an input shaft coupled to said motor means; and an output shaft;

acceleration/deceleration means coupled to said clutch means output shaft and having an output shaft coupled to said blade means;

said clutch means including means responsive to said trigger signal for abruptly accelerating its output shaft to a constant angular velocity an maintaining rotation at said constant angular velocity and abruptly halting rotation of its output shaft upon completion of one full revolution;

said acceleration/deceleration means comprising means responsive to rotation of said clutch means output shaft for smoothly and gradually accelerating its output shaft from zero velocity towards an angular velocity of the order of twice its input velocity and thereafter smoothly and gradually decelerating its output shaft so as to bring its output shaft substantially to zero velocity as the output shaft completes one full revolution.

7. The stacker of claim 1 further comprising backstop means;

said stacking means comprising reciprocally mounted stacking blade means having an upper position extending through said backstop means and cooperating with said backstop means to receive and collect signatures from either said blade means or said infeed conveyor means;

said stacking blade means further having a lower position displaced from said backstop means to enable signatures deposited and collected thereon to be transferred to a bundle collecting table positioned beneath said upper position;

means for moving said stacking blade means to said lower position and rapidly return said stacking blade means to said upper position in readiness for receipt of the next bundle.

8. The stacker of claim 7, wherein said collecting table further comprises rotatably mounted turntable means;

means for rotating said turntable to form compensated bundles.

9. The stacker of claim 8 further comprising pusher means including a pusher arm and air driven cylinder means for reciprocally moving said pusher arm along a horizontal path between first and second end points to push completed bundles out of said turntable.

10. The stacker of claim 9 wherein said cylinder means comprises means for moving said pusher arm in a first direction at a first velocity when pushing a bundle out of said turntable and for moving said pusher arm in the reverse direction at a second faster velocity of return said pusher arm to its original position in readiness for pushing the next bundle in said first position.

11. The stacker of claim 10 further comprising first and second proximity sensing means positioned adjacent the end points of travel of said pusher arm for respectively detecting the position of said pusher arm to permit rotation of said turntable only when said pusher arm is at one of said end points.

12. The stacker of claim 11 further comprising third proximity sensing means positioned intermediate the end points of travel of said pusher arm and responsive to said pusher arm passing thereby for generating a signal;

said cylinder means being adapted to reverse said pusher arm when said pusher arm passes said third sensing means.

13. The stacker of claim 12, wherein said pusher arm air cylinder comprises first and second air ports positioned at opposite ends of said air cylinder, T-connector means for coupling a source of pressure to each port and first and second normally closed quick air release ports further coupled to said air cylinder ports and adapted to be selectively open when moving said pusher arm in said reverse direction to facilitate movement of the pusher arm at a faster velocity.

14. The stacker of claim 6, wherein the coupling between the output shaft of said single revolution clutch means and the acceleration/deceleration means is adjusted to cause the blade means to decelerate to zero velocity and then to accelerate a predetermined amount before said single revolution clutch means is deenergized.

15. The stacker of claim 1, further comprising one-way clutch means coupled between said blade assembly and said rotating means for preventing any rebounding of said blade means in a direction opposite said first direction upon movement of said stop means towards said withdrawn position.

16. The stacker of claim 1 further comprising maximum torque protection clutch means coupled between said blade assembly and said rotating means for disengaging the driving force of said rotating means from said blade assembly when the driving force exerted by said rotating means exceeds a predetermined threshold.

17. The stacker of claim 16 wherein said clutch means comprises a driving output shaft; retractable pin means; a hollow cylinder surrounding said output shaft and having a recess for receiving said retractable pin; means normally engaging said outfeed shaft for rotating said output shaft when said cylinder is rotated, to drive said blade assembly when said pin is seated within said opening;

said means being responsive to a maximum torque threshold condition for withdrawing from said opening and releasing said shaft engaging means to enable said cylinder to be free-wheeling relative to the shaft to thereby prevent said blade assembly and said stop means from being damaged.

18. The stacker of claim 17, wherein said pin means is prevented from entering said recess when the relative rotation between said pin and said cylinder exceeds a predetermined angular velocity to prevent said blade means from being rotated when the angular velocity imparted to the clutch means is too high.

19. The conveyor means of claim 1 wherein said infeed conveyor means comprises

a first upper conveyor means;

a first lower conveyor means positioned beneath said upper conveyor means;

the lower run of said upper conveyor means being diagonally aligned to form a tapered infeed region with the upper run of said first lower conveyor means for receiving said signature stream;

second upper conveyor means postioned adjacent the downstream end of said first upper conveyor means;

second lower conveyor means positioned adjacent the downstream end of said first lower conveyor means, whereby the lower run of said second downstream upper conveyor means and the upper run of said second downstream lower conveyor means are adapted to receive said signature stream therebetween;

the downstream end of said second upper and lower conveyor means comprising

a pair of cooperating rollers defining the downstream end of said infeed conveyor means;

means for rotating said rollers to cause said rollers to compress the signatures passing therebetween;

20. The conveyor means of claim 19, wherein said swingable mounting means comprises first and second pivotally mounted arms each adapted to swing about a stationary pivot point;

air cylinder means mounted between said first and second pairs of swingable arms for urging said rollers towards one another to squeeze signatures passing therebetween, the urging force exerted upon said rollers being substantially linear and independent of the spacing between said rollers.

21. The conveyor means of claim 20, wherein said infeed rollers each have a substantially V-shaped configuration for imparting a similar shape to signatures passing therebetween to facilitate handling and stacking of the signatures.

22. A turntable assembly for receiving and stacking a bundle of signatures delivered thereto from an intermediate stacking means comprising

means for rotating said turntable assembly;

pusher means including a pusher arm and air driven cylinder means for reciprocally moving said pusher arm along a horizontal path between first and second end points to selectively push completed bundles in either direction; said cylinder means being positioned above said turntable assembly and between said end points.

23. The device of claim 22, wherein said cylinder means comprises means for moving said pusher arm in a first direction at a first velocity when pushing a bundle out of said turntable and for moving said pusher arm in the reverse direction at a second faster velocity to return said pusher arm to its original position in readiness for pushing the next bundle in said first direction.

24. The device of claim 23 further comprising first and second proximity sensing means positioned adjacent the end points of travel of said pusher arm for respectively detecting the position of said pusher arm to permit rotation of said turntable only when said pusher arm is at one of said end points.

25. The device of claim 24 further comprising third proximity sensing means positioned intermediate the end points of travel of said pusher arm and responsive to said pusher arm passing thereby for generating a signal;

26. The device of claim 25 wherein said pusher arm air cylinder comprises first and second air ports positioned at opposite ends of said air cylinder, T-connector means for coupling a source of pressure to each port and first and second normally closed quick air release ports further coupled to said air cylinder ports and adapted to be selectively open when moving said pusher arm in said reverse direction to facilitate movement of the pusher arm at a faster velocity.

93/93C; 93/93R; 271/189

B31B 198

2819661 January 1958 Howdle et al.
3306173 February 1967 Robinson
3479932 November 1969 Stal et al.
3526170 September 1970 Oderman et al.
3617055 November 1971 Stal
3772972 November 1973 Dutro et al.
3908985 September 1975 Wiseman

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