ZIG-ZAG FOLDING MACHINES

Abstract: First and second parallel folding rollers (6 and 7) respectively co-operate with third and fourth folding rollers (4 and 5) of folder means to form first and second folding devices (4, 6 and 5, 7). Non-return feed rollers (8 and 9) are mounted between the first and second folding rollers (6 and 7) for folding pliable strip material (3) alternately to the two folding devices (4, 6 and 5, 7) and an intermediate part (14) of the folder means extends between the third and fourth folding rollers (4 and 5) so as to act as a guide for the pliable strip material (3). Movable guide means (12) are operable to deflect the leading end (24) of the pliable strip material (3) towards the first folding devices (4 and 6).

Description: Zig-Zag Folding Machines Technical Field of the Invention The invention relates to Zig-Zag folding machines for the concertina-like folding of pliable strip material, suit¬ able for use in folding engineering drawings and the like. Background Art As disclosed in the van der Grinten Bulletin of 22nd June 1967, one kno * wn form of Zig-Zag folding machine comprises folder means having first and second parts; first and second spaced folding rollers respectively co-operable with the first and second parts of the folder means to form first and second spaced folding devices; non-return feed means which prevent return movement of pliable strip material fed between the first and second spaced rollers; and movable guide means for directing the pliable strip material towards at least one of the spaced -foi ding devices. In this prior art olding machine , the first and second parts of the folder means respectively constitute third and fourth folding rollers and the folder means include an intermediate part extending between the third and fourth folding rollers and providing a fixed guide surface for the pliable strip material. The non-return feed means of this -machine comprise a pair of feed rollers disposed upstream of the first and second folding rollers , ' at the entrance of the path of the pliable strip material between the first and second folding rollers. The movable guide means of the machine constitute an oscillatory guide ex¬ tending from a fixed guide which extends downstream from the feed, rollers and is movable between two positions in which the pliable strip material is directed, respectively, into the nip between the first and third folding rollers and into the nip between-the-second-and fourth folding-- rollers - .I operation, the first and second folding rollers always rotate in the same direction as each other, first one way and then the other. The third and fourth rollers always rotate in the opposite direction to the first and second rollers. The first and second folding devices therefore alternate in rotating in such a way as to provide a fol¬ ding nip for the pliable strip material from the feed . rollers. To start the folding operation, the oscillatory guide is pointed towards the first and third folding rollers which are rotated in such a way as to provide a folding nip and the leading end of the strip material is fed between the feed rollers , through the oscillatory guide and between the first arid third rollers constituting the first foldin device. All the folding rollers are then stop and rotate in the opposite direction and the oscillatory guide is swung away from its initial position until it is pointing towards the second and fourth folding rollers. As a result of the continuing operation of the feed rollers and the reverse rotation of the frist and third folding rollers , a loop is formed in the pliable strip material and this loop is fed into the nip between the second and fourth folding rollers to form a first fold. All the folding rollers are then stop once again and then rotated in ' the first direction. Another loop is formed in the pliable strip material and this loop is fed into the nip between the first and third folding rollers to form a second fold. Third, fourth, and subsequent folds may be formed in a completely analogous manner. However , difficulty is incounted in providing means for synchronising movement of tne oscillatory guide with the changed indirection of ro-fcation ~ of the- folding "rollers - and with the rate at which slack is formed in the pliable sheet material so as to result in the controlled forma¬ tion of loops which are fed alternately between the rol¬ lers of the first and second folding devices. It is ' therefore impossible to obtain completely accurate folding with adjacent folds lying on top of each other. In a less complex, less costly, less bulky and less diffi¬ cult to operate folding machine of similar construction, disclosed in US Patent No. 3 7 _7 917, the first and second parts of the folder means comprise peripherally spaced portions of a single roller or spaced portions of an end¬ less band trained around two parallel rollers. The non- . return feed means of this machine do not feed the pliable strip material between the first and second rollers and into the nips provided by the first and second folding devices , but allow this movement and prevent movement of the pliable strip material in the opposite direction. ' Finally, the movable guide means of this machine are pro¬ vided by an intermediate part of the folder means ex¬ tending between the first and second parts. Thus, in one embodiment, the movable guide means are provided by a circum erential portion of the single roller and in another embodiment the movable guide means are. rovided by a part of the endless band providing the first and • second parts of the folder means. Thus, as the leading edge of the pliable strip material is fed between the first and second rollers and into engagement with the intermediate part of the folder means, movement of the folder means deflects the leading edge of the pliable strip material into which ever of the nips between the first and second folding devices towards which the intermediate parts is moving. In this way, as with the oscillatory guide, the first fold is formed at a predetermined— i&tance from— he—leading-edge-of the * _ _ _ pliable strip material., Un ortunately, the intermediate part of the folder means does not provide positive guidance for the pliable strip material-and, because the speed of the intermediate part of the folder means is limited to the speed at which the pliable strip material is fed into the first and second folding devices , there is unwanted slipage between the pliable strip material and the intermediate part of the folder means and this results in inaccurate folding. Disclosure of the ' Invention It is intended, by means of the present invention, to provide a Zig-Zag folding machine having a movable guide which is more effective in directing the pliable strip material into the nips of the first and second folding devices than in prior art machines and yet not so diffi¬ cult to control as the known oscillatory guides. This objective is provide by ensuring that the first and second parts of the folder means comprise third and fourt rollers; the folder means include an intermediate part between thr irst and second part ; and the movable guide means are mounted between the third and fourth folding rollers and capable of movement relative to the inter¬ mediate part of the folder means. Thus, according to the invention, there is provided a Zig-Zag folding machine, for the concertina-like folding of pliable strip material, comprising folder means having first and second spaced folding rollers rotatable about parallel axes , folder means having third and ourth folding rollers and then intermediate part extending between the third and fourth folding rollers , the third and fourth folding rollers being cooperable, respectively, with the - irst and -se-cond. -f-ol<iing-rollers to form first and second folding devices; non-return feed means. hich prevent return movement of pliable strip material fed between the first and second folding rollers; and movable guide means mounted between the third and fourth folding rollers and capable of movemnet relative to the inter¬ mediate part of the folddr means or -directing the pliable strip material towards at least one of the spaced folding devices. Because, in this form of construction, the intermediate part of the folder means remains stationary, it is pos¬ sible to mount the movable guide means in this part of the machine for movement relative to the intermediate part of the folder means. One consequence of this arrangement is that the non-return feed means may be situated closer to the nips provided by the first and second folding devices, thus ensuring that there is less space for the pliable strip material to be deflected from its desired path so as to cause foϊding inaccuracies. Another consequence is that the limations on the control and effectiveness of the movable guide means can be more easily overcome. Thus, in one preferred embodiment of the invention, the movable .guide means may be mounted for pivotal movement about an axis extending parallel to the axes of the first and second folding rollers for pivotal movement between a retracted position in which the movable guide means extend between the third and fourth folding rollers and a deflecting position in which the movable guide means obliquely intersect the axis of movement of the pliable strip material through the non-return feed means so as to deflect the pliable strip material towards one of the first and second folding devices. This movemen_t may be affected by a reciprocable plunger such as a solenoid core or the piston of a piston-cylinder assembly fed with pressurised-f-iuidy -so -as -to operat-e -independently drive means or rotating the irst and second rollers. With this form of-construction, the pivotal axis of the guide means may be disposed on the opposite side of the intermediate part of the folder means to the non-return feed means; the intermediate part of the folder means may be formed with at least one elongate opening; and the movable guide means may be provided with a portion which is movable through the elongate opening in the inter¬ mediate part of the folder means on movement of the movable guide means from -their retracted position to thei deflecting. Thus, where the movable guide means are pro¬ vided with a series of fingers , the intermediate part of the folder means is provided with a plurality of parallel slots, - each of which allows one of the fingers to move from one side of the intermediate part of the folder mean to the other. With this form of construction, it is pos¬ sible to orm at least one of the feed rollers with . a plurality of c±rcum erentially extending grooves for receiving the tips of these fingers so as to ensure that, the movable guide means are moved into suffeciently close proximity to the pliable strip material to deflect the leading edge of the strip material effectively into the folding nip provided by one of the first and second fol¬ ding devices. With this form of contructio , adequate deflection is provided by the guide means when in their deflecting position, but when the movable guide means are withdrawn to their retracted position, the passage of pliable, strip material between the first and second fol¬ ding devices is facilitated by the guidance provided by the intermediate part of the folder means. In another preferred embodiment of the invention, the movable guide.means are mounted for rotation about an axi extending parallel to the axes of the first and second folding jrollers -and disposed on .the. opposite side of the intermediate part of the folder means to the non-return feeding means. ' The intermediate part of the folde means is formed with at least one opening,' through which part of the movable guide means extends , further drive means are provided for rotating the movable guide means in op¬ posite directions; and the outer periphery of the movable guide means provides and irregular surface for alter¬ nately directing the pliable strip material towards the first and second folding devices. To provide a suitably irregular surface , the movable guide means may comprise one or more series of spokes or radial projections having outer ends which are circumferentially spaced apart. A slot or opening may be formed in the intermediate part of the folder means to permit the outer extremities of the spokes of radial projections in each such series to extend into the axis of the path of move¬ ment of the pliable strip material through the non-reutrn feed means. Irt. an alternative arrangement, the movable guide means may comprise one or more discs having roughened peripheries and mounted so that parts of these peripheries extend through slots formed in the intermediate part of the older means. To improve the effectiveness of these rotary guide means, the guide means may be rotated at a greater circumferen— tial speed than the first and second rollers. Thus, the circumferential speed of the rotary guide means may be three or four times as high as the circumferential speed of the first and second folding rollers. Two embodiments of the invention are hereinafter described, by way of example, with reference to the .accompanying drawings. - 8 - Brief Description of the Drawings Figures 1, 2 and 3 -are sectional side elevations of a . first embodiment of the invention, showxng three succesiv stages in the Zig-Zag folding of a pliable strip material and Figures 4 and 5 are sectional side elevations of a second embodiment of the invention, showing two sucessive stages in the folding operation. Exemplary Modes for Carrying Out the Invention In the Zig-Zag olding machine 1, showing in Figures 1 to 3, pliable strip material 3 is fed, for example, from a printing machine (not shown) , ' through a sheet matal guide 20 which is provide with recesses (not shown) so as to allow the strip material 3 "to engage a freely rotable guide roller 21 and a clamping roller 22 mounted on a pivotal arm 23 so as to rest on the guide roller 21. Feed rollers 8 and sire mounted at the outlet end of the guide 20 and are driven so as to feed the strip material through the machine 1. Movable .guide means 12 are provided with a plurality of fingers l6 and, when in their position, as shown in Figu Figure 1, the fingers l6 intersect the axis of movement of the strip material 3 from the eed rollers 8 and 9 so as to deflect the leading end 24 of the strip material 3 into a folding nip between a frist folding 6 which is mounted on a pivotal arm 25 so as to rest on a third folding roller 4 which, is driven, as scarqatically shown, by a roller chain 26 and sprockets 27 and 28. As shown, the movable guide means 12 are mounted for rotation on a shaft extending parallel to the axis of the first olding roller 6 and -a-roHer-chain -29- is trained around a sprocket 30 mounted on this shaft. One end of the roller chain 20 is connected to an anchored tension spring 31 and the other end of the roller chain 29 is connected to the core 15 of a solenoid 32 which, as shown in Figure 1, has been actuated so as to extend the tension spring 31 and lift the fingers l6 of the movable guide . means 12 upwards into the deflecting position of the movable guide means 12. When suffecient sheet material 3 h s been fed- through the first " folding device provided by the first and third ol¬ ding rollers 6 and 4, the solenoid 32 is de-energised, thus allowing the tension spring 31 to withdraw the core 15 of the solenoid 3 sb as to allow the movable guide means 12 to move into a retracted position as shown in broken outline in Figure 1. At the same time, first and third folding rollers 6 and 4 are stoped and rotated by the prime mover 11 in the opposite direction. As a result, both the feed rollers 8 and 9 and the first and third folding rollers 6 and 4 feed strip material towards each other so as to form a loop which moves away from the first folding device, as shown in Figure 2. This loop is eventually fed into a folding nip between a second folding roller 7 -and a fourth folding roller • Although not shown, transmission means connect the prime mover 11 to the fourth roller 5 so that the ourth roller always rotates in the same direction as the third roller 4. Similarly, the second roller 7 is mounted on a pivotal •arm 33 so as to rest on the fourth roller 5 and so the second folding roller 7 always rotates in the same direc- tion as the first folding roller 6. As the loop shown in Figure 2 passes through the nip between the second and ourth* olding rollers 7 and 51 a fold-is formed-i -the strip-_αa er_ial-3. The four folding MFI 'J rollers 4 to 7 are driven in the reverse direction, as shown in Figure 2 until the leading end 24 of the strip material is withdrawn from the nip between the first and third, folding rollers 6 and 4. The folding rollers 4 to 7 are then stoped and, by means of the prime mover 11, are rotated in their original direction. As a result, a further loop is formed and this loop is eventually fed into the nip between the first and third folding rollers 6 and 4 so as to form a second fold. Third and subsequent folds are formed in a completely analogous manner so as to fold the pliable strip material 3 into a concertina¬ like formation, as shown in Figure 3• When the whole length of strip material 3 has been folded, the folding rollers . 4 to 7 are rotated in the original direction, as shown in Figures 1 and 3 until the concer¬ tina-like formation is fed right through the nip between the first and third folding rollers 6 and 4. The folded formation is t en ejected from the folding machine through discharged rollers 3*^ and 35- Although not shown, the feed rollers 8 -and 9 -and the discharged rollers 34 and 35 are all drivably connected to the prime mover 11. The third and fourth folding rollers 4 and constitute first and second parts of folder means which also include an intermediate part l4 in the form of a fixed guide ex¬ tending between the third and fourth rollers 4 and for supporting the strip material 3 and the concertina-like formation as the concertina-like formation is reciprocated between the first and second folding devices formed, res¬ pectively, by the first and third folding, rollers 6 and 4 and the second and fourth folding rollers 7 and 5- How¬ ever, as shown in Figures 1- to 3 the movable guide means 12 are mounted for pivotal oscillation about an axis dis¬ posed on the opposite side of the intermediate part l4 to the -feed-rollers--8 -and -9 » so as to-al-low 8 and 9 to be located as close as possible to the inter¬ mediate part l4~ Therefore, in order to allow the . movable guide means.12 to move from their retracted posi¬ tion to their deflecting position, the intermediate part l4 is formed with a plurality of elongate dlots through which the fingers l6 are able to pass. Similarly, a plurality of circumferential grooves 17 are formed in the feed roller 9 so as to accommodate the extremities of the fingers l6 , thus permitting the movable guide means to be moved into a deflecting' position in which they are most effective in deflecting the leading end 24 of the pliable strip material • In the Zig-Zag folding machine 2 constituting the second embodiment of the invention illustrated in Figures 4 and 5, much of the machine is identical to the machine 1 shown in Figures 1 to 3 and corresponding reference nume numerals have been assigned to like parts. However, in this second embodiment, the movable guide means are in " - the form of rotary guide means 1 driven by a second prime mover 36 which, as shown scamatically, is connected to the rotary guide menas 30 by means of a roller chain 37 and sprockets 38 -and 39 so that the peripheral speed of the rotary guide means 13 is three times the peripheral speed of the four folding rollers 4 to 7- In operation, the roteiry guide means 13 always rotate in the same direction as the third and fourth folding rollers 4 and and so , when the leading end 24 of the pliable strip material 3 is fed between the feed rollers 8 and 10 , which in this case both have uniterrupted cylindrical surfaces, the leading end 24 is flicked towards the nip between the first and third folding rollers 6 and 4 so as to ensure that the length of strip material 3 between the free end 24 . and . _the first fold can be accurately con— trolled. When the folding rollers 4 to 7 a e rotated in the re- . verse direction, so too is the rotary guide means 13i thus assisting in the formation of a loop -as shown in Figure . which is fed into the folding nip between the second and fourth folding rollers 7 and 5 to form the first fold. One benifitial effect of the high speed rotation of the rotary guide means 13 is that the pliable strip material 3 is kept taut. The rotary guide means 13 comprise a series of axially spaced sets of radial projections which have outer ends l8. As shown in Figures 4 and 5 each set comprises four equiangularly spaced .radial projections or spokes and these radial projections or spokes extend through slots formed in the intermediate part 14 extending between the third and fourth folding rollers 4 and so that the ex¬ tremities of these radial projections or spokes are able to engage the strip material 3- As shown in the drawings , both machines 1 and 2 are pro¬ vided with sheet metal guide means 4 . for supporting the pliable strip material 3 and the concertina-like forma¬ tion produced by the machine. As shown, the upper parts of these guide means 40 extending between the feed rollers 8 and 9 r 10 and the first and second folding devices 4, 6 and 5 j 7 also cooperate with the intermediate part l4 extending between the third and fourth rollers 4 and to direct loops formed in the pliable strip material 3 into the nips provided by the two folding .devices. Although reference numerals have been used in the ap¬ pended claims , to improve the intelligibility of these claims, it is expressly stated that these reference nu¬ merals -should-not be -construed .as -limiting the .claims.to the constructions illustrated in the accompanying drawing

Claims: Claims 1- A Zig-Zag folding machine (l or 2), for the concertina¬ like folding of pliable strip material (3), comprising: folder means having first and second parts (4 and 5); • first and second spaced folding rollers (6 and 7) rota- table about parallel axes and respectively co-operable with the first and second parts (4 and 5) of the folder means to form first and second folding devices (4, 6 and 5, 7); " non-return feed means (8 and 9 or 10) which prevent return movement of pliable strip material ' (3) fed between the first and -second spaced folding rollers (6 and 7); drive means (ll) operable to drive the first and.second rollers (6 and 7) 1 directly ot indirectly, alternately both in one direction and then both in the opposite direc¬ tion; and movable guide means (12 or 13) for directing the pliable strip material (3) towards at least one of the spaced folding devices (4, 6 and 1 7) ; characterized in that: the first and second parts of the folder means comprise third and fourth folding rollers (4 and 5); the folder means include an intermediate part (l4) exten¬ ding between the third and fourth folding rollers (4 and 5) ; and the movable guide means (12 or 13) are mounted between the~third-and fo*u th-^old3_n_>—rollaθ3^s— 4--and—5-)--nd .capable. of movement relative to the intermediate part (l4) of the folder means. 2_ A machine (l), according to Claim 1, characterized in that the movable guide means (12) are mounted for pivotal movement about an axis extending parallel to the axes of the first and second folding rollers (6 and 7) between a retracted position in which the movable guide means (12) extend between the third and fourth folding rollers (4 an 5) of the folder means and a deflecting position in which the movable guide means (12) obliquely insect the axis of movement of the pliable strip material (3) through the non-return feed means (8 and 9) and deflects the pliable strip material (3) towards one of the first and second folding devices (4 and 6)'. 3. A machine (l), according to Claim 2, characterized in that the movable guide means (12) are operated by a reci- procable plunger (15)) independently of the drive means (ll) for the first and second folding rollers (6 and 7)- 4. A machine " (l), according to Claim 2, characterized in that: : the pivotal axis of the movable guide means (12) is dis- • posed on the opposite side of the intermediate part (l4) of the folder means to the non-return feed means (8 and 9); the intermediate part (l4) of the folder means is formed with at least one elongate opening; and - 15 - the movable guide means (12) are provide with a portion (16) which is movable through the elongate opening in the intermediate part (.14) of the folder means on movement of the movable guide means (12) from their retracted posi¬ tion to their deflecting position. 5. A machine (l), according to Claim 4, characterized in that: the movable guide means (12) are provide with a, plurality of said portions in the form of fingers (l6); the intermediate part (l4) of the folder means is formed with a plurality of elongate openings; the non-return feed me.ans comprise two feed rollers (8 and 9), at least one of which is positively driven; and at least one (9) of the feed rollers (8 and 9) is formed with a plurality of circumferentially extending grooves (17) for receiving the fingers (16) of the movable guide means (12). 6. A machine (l), according to Claim 1, characterized in that: the movable guide means (13) are mounted for rotation about an axis extending parallel to the axes of the irst and second folding rollers (6 and 7) and disposed on the opposite side of the intermedig.te part (14) of. the folder means to the non-return feeding means (8 and 10); a further drive means (19) are provided for rotating the movable guide means (13) in opposite directions; and URE. ( / ., * — OOMM-PP-II_ V.IΪO S the outer periphery of the * movable guide means (13) pro¬ vides an irregular surface for alternately directing the pliable strip material (3) towards the first and second folding devices (4, 6 and 5» 7)« 7. A machine (2), according to Claim 6, characterized in that the movable guide means (13) rotates with a greater circumferential speed than the first and second folding rollers (6 and 7).

Inventors: ASHBURNER A
Applicants: ASHBURNER A, HARPER & TUNSTALL LTD
Application year: 1981
Main classification: B65H45
IPC codes: B65H45