FOLDING APPARATUS

Abstract: A folding apparatus in which an intermediate span of a signature (S) at the folding station is buckled by a pair of oppositely driven signature feeding surfaces (14,15) into the nip of a pair of converging signature folding and feeding surfaces (12,13) which fold the signature and feed it from the folding station.

Description: The present invention relates to a folding apparatus comprising a pair of signature folding surfaces moving in converging directions for receiving an intermediate span of a signature at a folding station, folding said signature and discharging it from the folding station, wherein the signature to be folded is fed to said folding station between upper and lower conveyor belts to a position adjacent said pair of signature folding surfaces disposed on one side of the signature. Although the folding apparatus of the present invention has a more general application, it is particularly adapted to produce "chop" folds in printed signatures, that is to say, a fold that is perpendicular to a signature that has already been jaw folded. Printed signatures are often "jaw" folded across the width of the signature and then "chop" folded along a line perpendicular to the jaw fold. The jaw fold is made by a tucker blade carried by one cylinder and a jaw carried by an adjacent cylinder. The paper is fed between the tucker blade and the jaw, and the jaw imparts a crease or fold line into the signature. If the jaw folded signature is to be chop folded, the jaw folded signature is fed to a chop folding station situated above a pair of signature folding surfaces moving in converging directions and below a chopper blade which descends, forcing the signature into the nip between the pair of signature folding surfaces which fold the signature and discharge it from the folding station. Chopper blades have long been used for producing chop folds, but they have many drawbacks, inter alia , the folds which they produce are not accurate and precise, they do not lend themselves to high speed operation, they tend to damage the signature and they give rise to design and critical adjustment problems. The chopper blade feeds the signature into the nip of the signature folding surfaces by rapidly descending against the signature in the folding station, and the signature is free to move or slip relative to the blade because there is no provision for controlled feeding of the signature into the nip. Such undesirable movement or slipping of the signature relative to the blade will cause defective folding of the signature. DE-A-1 411 773, corresponding to the preamble of claim 1, discloses a chop folding apparatus employing a chopper blade mounted on a rotating blade support. To adjust the position of the chopper blade relative to the signature to be folded the rotating blade support can be displaced along its axis of rotation. The amount of displacement in axial direction is automatically controlled by means of photocells which monitor the position of the incoming printed signature to be folded which is fed to the folding station between upper and lower conveyor belts. Whereas this chop folding apparatus may solve some problems associated with positioning the signature to be folded relative to the chopper blade, it can still damage the signatures, for example, by imparting crumpled edges and "dog ears", due to the action of the blade and signature folding surfaces on the signature. Ideally, the blade should push the signature into the nip gradually, but in practice the blade must be designed to accelerate the signature to a velocity above that of the folding surfaces. As the blade slows down before it reverses direction, the signature is thrust into the nip, abruptly decelerating the leading edge of the signature while the trailing ends attempt to overrun the leading edge, thereby resulting in the crumpled edges and "dog ears". In conventional chop folding apparatus, the signature can also be damaged by the stops used to stop and register the signatures at the folding station. Brushes are sometimes used to slow the signature before it encounters the stops. However, the design and adjustment of the slowdown brushes is critical and can result in jam-ups. Moreover, in conventional chop folding apparatus, the adjustment of the nip of the signature folding surfaces is critical. Since the chopper blade thrusts the signature into the nip, the nip must be carefully designed and adjusted to catch the signature and draw it into the nip. This critical adjustment must be changed with changes in the thickness of the signature to be folded. Failure to make the adjustment with precision will cause problems. The folding apparatus of the present invention provides a novel and improved means, as disclosed in claim 1, for feeding a signature from the folding station into the nip of the pair of signature folding surfaces which fold the signature and discharge it from the folding station while overcoming the disadvantages of conventional chopper blade feeds. The intermediate span of the signature is gradually fed into the nip between the pair of signature folding surfaces without causing damage to the signature. Moreover, since the leading edge of the signature is introduced into the nip while the trailing portions of the signature are still engaged and fed by the pair of oppositely moving signature feeding surfaces, there is no tendency of the trailing ends of the signature to overtake the leading folded edge. In a preferred embodiment of the folding apparatus of the present invention the pair or rotors are carrying signature engaging and feeding means for engaging spaced apart surfaces of a signature at the folding station and feeding the intermediate span of the signature into the nip of the pair of folding surfaces. The oppositely driven rotors can be mounted for rotation on a common axis or on eccentric axes. Each of the rotors carries a buckle prevention surface in advance of the signature engaging and feeding surface so that the intermediate span of the signature is directed between the pair of signature folding surfaces and prevented from buckling in the wrong direction. In a further preferred embodiment of the folding apparatus, the pair of oppositely moving braking and feeding surfaces are located outwardly of the inner oppositely moving signature feeding surfaces. These oppositely moving braking and feeding surfaces stop the signatures in registered position in the folding station and then feed the outer or trailing ends inwardly toward the pair of signature folding surfaces. These braking and feeding surfaces afford additional control over the trailing ends of the signature. When the trailing ends of the signature are released from the outer pair of oppositely moving braking and feeding surfaces, this control is maintained by the inner pair of oppositely moving signature feeding surfaces, which continue to feed the trailing ends of the signature until the leading edge has been folded and is being discharged from the folding station by the pair of signature folding surfaces. For a complete understanding of the present invention, reference can be made to the detailed description which follows and to the accompanying drawings in which: Figure 1 is a schematic front elevational view of the folding apparatus of the present invention; Figure 2 is an enlarged view of part of the folding apparatus shown in Figure 1; Figure 3 is a view taken along line 3-3 of Figure 2 looking in the direction of the arrows; Figures 4A, 48, 4C and 4D are enlarged views showing the pair of oppositely moving signature feeding surfaces progressively feeding a signature between said pair of signature folding surfaces; and Figure 5 is a cross-sectional view of the supporting shaft for the oppositely driven signature feeding rotors, showing eccentric axes of rotation for the rotors. In the folding apparatus of the present invention, a printed signature S to be folded is fed between upper and lower conveyor belts 10 and 11, respectively, to a folding station situated between a pair of signature folding surfaces 12, 13 moving in converging directions beneath the signature and a pair of oppositely moving signature feeding surfaces 14, 15 above the signature. As shown in Figures 4A through 4D, the pair of oppositely moving signature feeding surfaces engage the signature at spaced apart points and feed the intermediate portion of the signature between the pair of signature folding surfaces 12, 13, which fold the signature and discharge it from the folding station. If the signature S has been jaw folded, the signature will ordinarily be fed to the folding station by the conveyor belts 10, 11, with the jaw fold as the leading edge of the signature. The fold line produced by the folding surfaces will be perpendicular to the jaw fold. The signature folding surfaces are feeding tapes 12 and 13, which are driven in separate closed paths by a drive roller 16. The tapes 12 are guided in one closed path around idler rollers 17, 18, 19 and 20. A roller 21 supported by pivotal arms 22 engages the span of the tapes 12 intermediate the idler rollers 17 and 18 to take up slack. The tapes 13 are guided in a separate closed path around idler rollers 23, 24 and 25. A roller 26 supported by pivotal arms 27 engages the span of the tapes 13 intermediate the idler rollers 23 and 24 to take up slack. The drive is transmitted from the tapes 12 to the tapes 13 by a gear 28 carried by the idler roller 19, which meshes with a gear 29 carried by the idler roller 25. If desired, the tapes can be recessed in the rollers 18, 24 so that the rollers will function as the signature folding surfaces. As shown in Figure 1, the pair of oppositely moving signature feeding surfaces 14, 15 engage the signature at spaced apart points and feed the intermediate portion of the signature between the signature folding tapes 12, 13. As the intermediate span of the signature is gradually buckled and fed into the nip defined by the surfaces of the tapes 12, 13, the signature is folded and carried from the folding station between parallel spans of the tapes to a collector fan wheel 30. The signatures are discharged from the collector fan wheel by a stripper 31 onto a conveyor 32 for further processing. If desired, a creasing roller (not shown) can be provided adjacent the idler roller 19 to apply additional forces between the tapes 12, 13 to provide a sharper fold line in the signature. The signature feeding surfaces 14 are carried by a plurality of rotors 33 mounted for rotation in one direction on a shaft 34. The signature feeding surfaces 15 are carried by a plurality of rotors 35 mounted for rotation in the opposite direction on the same shaft 34. The shaft 34, as shown in Figure 3, is mounted between a pair of frames 36. As shown in Figure 3, the rotors 33 and 35 are arranged alternately on the shaft 34 either on a common axis or, as shown in Figure 5, on eccentric axes. The rotors 33 are driven in synchronism in one direction and the rotors 35 are driven in synchronism in the opposite direction. As best shown in Figures 4A through 4D, the outer periphery of each of the rotors 33 has a recessed portion 33a, which does not interfere with the delivery of the signature S to the folding station by the conveyor belts 10, 11, a raised surface 33b in advance of the signature feeding surface 14 to prevent the reverse buckling of the signature in the wrong direction and a surface 33c following the signature feeding surface 14 and of approximately the same radius as the surface 33b to guide and prevent whipping of the trailing end of the signature as it is fed from the folding station between the converging folding tapes 12, 13. The outer periphery of each of the rotors 35 has corresponding surfaces 35a, 35b and 35c which perform the same functions as the corresponding surfaces of the rotors 33. When the signature S is fed into the folding station by the conveyor belts 10, 11, its forward advance is stopped in proper registration in the folding station by the engagement of a pair of oppositely moving sheet braking and feeding surfaces 37, 38 which initially engage the signature to stop its forward advance and then cooperate with the sheet feeding surfaces 14, 15 to direct the signature between the converging folding tapes 12, 13. The signature braking and feeding surface 37 is carried by a supplementary rotor 39, mounted on a shaft 40 for rotation in one direction, and the signature braking and feeding surface 38 is carried by a supplementary rotor 41, mounted on a shaft 42 for rotation in the direction opposite from the shaft 40. The shafts 40 and 42 are mounted for rotation in bearings 43 which, in turn, are mounted to the frames 36. The signature braking and feeding surfaces 37, 38 engage the signature at the same time as or, if preferred, slightly in advance of the engagement of the signature by the signature feed surfaces 14, 15. The signature braking and feeding surface 37 cooperates with the upper surface of the feed tapes 12 while in engagement with the idler roller 17 (or with the upper surface of the roller 17 if the feed tapes 12 are recessed therein) to stop and then feed one trailing end of the signature toward the converging spans of the folding tapes 12, 13. In the same manner, the signature braking and feeding surface 38 cooperates with the upper surface of the feed tapes 13 while in engagement with the idler roller 23 (or with the upper surface of the roller 23 if the feed tapes are recessed therein) to stop and then feed the other trailing end of the signature toward the converging spans of the folding tapes 12, 13. As soon as the signature is stopped by the braking and feeding surfaces 37, 38, the signature feeding surfaces 14, 15 begin to feed the intermediate span of the signature into the nip of the converging folding tapes 12, 13. The signature feeding surfaces 14 cooperate with the upper surfaces of the tapes 12 while in engagement with the idler roller 18 (or with the roller 18) in feeding the signatures, and the signature feeding surfaces 15 cooperate with the upper surfaces of the tapes 13 while in engagement with the roller 24 (or with the roller 24). The shafts 40, 42 are rotated in opposite directions by a timing belt 44 driven by a sprocket 45 on a drive shaft 46. The timing belt is guided by an idler roller 47, passes around a sprocket 48 mounted on the shaft 42, engages a sprocket 49 mounted on the shaft 40 and then returns to the drive sprocket 45. The drive shaft 46 carries another sprocket 50, which drives the feed tape drive roller 16 through a timing belt 51 which engages a sprocket 52 on the drive roller 16. The rotors 33 on the shaft 34 carry sprockets 54 through which the rotors 33 are driven in one direction, and the rotors 35 also in the shaft 34 carry sprockets 55 through which the rotors 35 are rotated in the opposite direction. The sprockets 54 of the rotors 33 are driven by belts 56 from sprockets 57 mounted on the shaft 40. The sprockets 55, in turn, are driven by belts 58 from sprockets 59 mounted on the rotatable shaft 42. In the operation of the folding apparatus, the signature S is fed to the folding station by the conveyor belts 10, 11, and the recessed surfaces 33a, 35a of the rotors 33, 35, respectively, and the recessed surfaces of the supplementary rotors 39, 41 provide a passage for the incoming signature and do not interfere with its entry into the folding station. At the appropriate time the braking and feeding surfaces 37, 38 of the supplementary rotors 39, 41, respectively, will engage and stop the signature in a registered position in the folding station, the position shown in Figure 4A. The signature feeding surfaces 14, 15 may be timed to cooperate with the braking and feeding surfaces in stopping the incoming signature or to engage and feed the signature after it has been stopped. In either case, as shown in Figure 4B, the signature feeding surfaces 14, 15 will cooperate with the braking and feeding surfaces 37, 38 to feed and buckle the signature into the nip of the folding surfaces of the tapes 12, 13 and/or the rollers 18, 24. The oppositely moving feeding surfaces 14, 15 direct the leading folded edge of the signature at approximately the same velocity as the tapes 12, 13, while the trailing ends of the signature are being advanced to approximately the same velocity by the braking and feeding surfaces 37, 38. At this time the buckle prevention surfaces 33b and 35b are directly above the signature to prevent the signature from buckling in the wrong direction. The signature is gradually fed between the converging tapes 12, 13, which fold the signature and feed the leading edge of the signature to discharge it from the folding station as shown in Figure 4C. As the tapes 12, 13 take over the feed of the folded signature away from the folding station, the braking and feeding surfaces 37, 38, which have heretofore controlled the feed of the trailing ends of the signature, release the trailing ends of the signature, but the control of the feed of the trailing ends is taken over by the signature feeding surfaces 14, 15. As shown in Figure 4D, the signature feeding surfaces 14, 15 disengage from the signature when the discharge of the signature from the folding station has been completely taken over by the tapes 12, 13. Nevertheless, the trailing ends of the signature are guided and prevented from whipping by the guiding surfaces 33c, 35c of the rotors 33, 35, respectively. The folding apparatus of the present invention produces accurate and precise folds because the signature is stopped and located in the folding station, and from the outset the signature is under the control of the braking and feeding surfaces 37, 38 and then under the control of the feeding surfaces 14, 15, so that shifting of the registered signature relative to the folding station is prevented. The leading edge of the signature is fed gradually into the nip of the converging folding tapes 12, 13, at the same velocity, while the trailing ends are controlled and advanced at about the same velocity to prevent damage to the signature. There are no critical design or adjustment problems inherent in the folding apparatus of the present invention, and higher speeds can be achieved without damage to the signature by reason of the elimination or the reliance on a massive reciprocating chopper blade feed.

Claims: A folding apparatus comprising a pair of signature folding surfaces (12, 13) moving in converging directions for receiving an intermediate span of a signature (S) at a folding station, folding said signature (S) and discharging it from the folding station, wherein the signature (S) to be folded is fed to said folding station between upper and lower conveyor belts (10, 11) to a position adjacent said pair of signature folding surfaces (12, 13) disposed on one side of the signature (S), characterized in that a pair of oppositely moving signature feeding surfaces (14, 15) disposed on the opposite side of the signature (S) are engagable with the signature (S) at spaced apart points to buckle said intermediate span of the signature (S) into the pair of signature folding surfaces (12, 13), said pair of signature feeding surfaces (14, 15) is carried by a pair of synchronized rotors (33, 35) driven in opposite directions, one signature feeding surface (14, 15) being disposed on each of the rotors (33, 35), the outer periphery of each of said rotors (33, 35) has recessed surfaces (33a, 35a) and raised surfaces comprising said signature feeding surfaces (14, 15), and a pair of oppositely moving signature braking and feeding surfaces (37, 38) is adapted to cooperate with the pair of signature feeding surfaces (14, 15) to feed the signature (S) into the pair of signature folding surfaces (12, 13) and stop said signature (S) in proper registration in the folding station. A folding apparatus as set forth in claim 1 including buckle prevention means adjacent one surface of said intermediate span of the signature (S) to prevent the intermediate span from buckling away from said signature folding surfaces (12, 13). A folding apparatus as set forth in claim 1 including a buckle prevention surface (33b, 35b) carried by each of the rotors (33, 35) in advance of the signature feeding surface (14, 15) to insure that the intermediate span of the signature (S) is directed toward said pair of folding surfaces (12, 13). A folding apparatus as set forth in claim 1 wherein the recessed surface (33a, 35a) carried by each of the rotors (33, 35) permits the entry of the signature (S) to the folding station prior to the engagement of the signature feeding surfaces (14, 15) with the signature (S) delivered to the folding station. A folding apparatus as set forth in claim 1 including a signature guiding surface (33c, 35c) carried by each of the rotors (33, 35) following the signature feeding surface (14, 15) to guide the trailing ends of the signature (S) when the leading end has been delivered to the folding surfaces (12, 13). A folding apparatus as set forth in claim 1 in which said pair of signature folding surfaces (12, 13) includes a pair of driven tapes, each guided in a closed path which paths converge to receive the intermediate span of the signature (S) and to fold the signature (S), said converging tapes being followed by a parallel span for discharging the folded signature (S) from the folding station. A folding apparatus as set forth in claim 6 in which said tapes cooperate with the pair of oppositely moving signature feeding surfaces (14, 15) to feed said intermediate span of the signature (S) into the pair of signature folding surfaces (12, 13). A folding apparatus as set forth in claim 1 in which the pair of signature feeding surfaces (14, 15) are located inwardly of said pair of signature braking and feeding surfaces (37, 38), so that the latter feed the trailing ends of the signature (S) while the former feed the signature (S) to buckle the leading end. A folding apparatus as set forth in claim 1 including a pair of spaced apart drive shafts (40, 42) driven in opposite directions and a common intermediate shaft (34) for said pair of rotors (33, 35) and including means (54, 56, 57) connecting one (40) of the drive shafts (40, 42) to drive one (33) of said pair of rotors (33, 35) and means (55, 58, 59) connecting the other (42) of said drive shafts (40, 42) to drive the other (35) of said rotors (33, 35). A folding apparatus as set forth in claim 1 in which there are a plurality of said rotors (33, 35) driven in opposite directions on a common shaft (34), each carrying said signature feeding surface (14, 15), and in which alternately spaced rotors (33) rotate in one direction and alternately spaced rotors (35) rotate in the opposite direction. A folding apparatus as set forth in claim 1 including a pair of supplementary rotors (39, 41) spaced apart and rotatable in opposite directions on parallel axes, and a signature braking and feeding surface (37, 38) carried by each of said supplementary rotors (39, 41), said braking and feeding surface (37, 38) being engagable with the signature (S) for stopping the signature (S) at the folding station and then cooperating with said pair of oppositely moving signature feeding surfaces (14, 15) to feed the intermediate span of the signature (S) between said pair of signature folding surfaces (12, 13). A folding apparatus as set forth in claim 11 including at least said pair of rotors (33, 35) driven in opposite directions on a common shaft (34) intermediate said parallel axes and in which said pair of rotors (33, 35) on said common shaft (34) are driven in opposite directions, said pair of oppositely driven rotors (33, 35) on the common shaft (34) carrying said oppositely moving signature feeding surfaces (14, 15) and cooperating with said braking and feeding surfaces (37, 38) to feed the intermediate span of the signature (S) into the pair of signature folding surfaces (12, 13). A folding apparatus as set forth in claim 1 in which said rotors (33, 35) rotate on a common axis of a common shaft (34). A folding apparatus as set forth in claim 1, in which said rotors (33, 35) rotate on eccentric axes of a common shaft (34).

Inventors: LOEBACH, MICHAEL H.
Applicants: LOEBACH, MICHAEL H.
Application year: 1988
Main classification: B65H45
IPC codes: B65H45, B41F13