GB2066783A - Folding machine - Google Patents

Abstract

A folding machine for a rotary printing machine, comprises a rotatable cylinder (1) provided around its circumference with an even number of equidistantly spaced pairs (I-IV) of pivotal folding blades (8, 11, 12) which are actuable by three cams (7, 9, 10). The folding blades (8) which trail in the rotational direction of the cylinder (1) are each actuatable by a first one of the cams (7) only at a product entrainment station (A), while the leading folding blades (11, 12) are actuatable by second and third ones of the cams (9, 10) only at product discharge stations (B, C), which may be disposed at two positions. All of the cams (7, 9, 10) rotate in the rotational direction of the cylinder (1) and the leading blades (11, 12) are associated, with respect to their sequence around the circumference of the cylinder (1), alternately with the second and third cams (9, 10). The rotational speed of all of the cams (7, 9, 10) is stepped in relation to that of the cylinder (1) in dependence on the number of blade pairs. Similarly, the cam track (19, 20 or 21) of each of the three cams (7, 9, 10) includes a plurality of equidistantly spaced actuating zones (55, 56 or 57) depending in number on the number of blade pairs. The second and third cams (9, 10) for controlling the leading blades (11, 12) are rotationally staggered relative to each other, either in opposition to their rotational direction if the cams are rotated faster than the cylinder (1) or in that rotational direction if the cams are rotated slower than the cylinder, by an angle alpha depending on the number of actuating zones (55,56) per cam track (19, 20) and on the angle beta subtended by the two positions of the product discharge stations (B, C). <IMAGE>

Description

SPECIFICATION Folding machine The present invention relates to a folding machine, and has particular reference to the controlling of the folding blades of a folding blade cylinder of such a machine.

In the folding of products it is often necessary after the provision of a first transverse fold formed in known manner by the co-operation of a folding blade cylinder, to provide the products with a second longitudinal fold, also termed a third fold. Since the operating speed of the device for the third fold is limited, two such folds are often needed in order to feed a printing machine at such a rate as to permit the printing machine to operate at an optimum output capability.

In a folding blade cylinder with an even number of folding blade pairs, it is known to discharge the product at a discharge station and to subsequently direct them via a controlled switch to two belt conveyors each connected to, for example, a device for providing the third fold. A disadvantage in this case is that usually the lower belt conveyor cannot extend sufficiently closely to the switch for the products to be accurately guided in the transfer region between the folding blade cylinder and belt conveyor. In addition, access in this region is restricted, which is a drawback especially during stoppages.

Independently of this, problems also arise in the controlling of the folding blades of high-speed rotary printing machines. The cam rollers running on stationary cams, and also the oscillating levers connecting the rollers to the folding blades, are subjected to high dynamic loadings as a consequence of the high relative speed between cam rollers and cam discs. Irregular running of the cam rollers, considerable noise output and high wear of associated gear mechanisms are the consequence.

In order to reduce the relative speed between the cam disc and cam roller, the diameter of the cam disc can be decreased as described in DE-PS 633 756 and DE-PS 2 316 227. However, this measure requires additional transfer elements, such as plungers, as compared with the conventional arrangement of an oscillating lever journalled at one end in the folding blade cylinder and carrying the cam roller at the other end. With the proposed solution to reduce the relative speed between cam disc and roller there is inevitably associated a rise in the inertia of the gear mechanism and a greater number of articulation points and guides for the transfer element, which, due to increased wear and imprecise transmission of movement, mitigates against an increase in output of the folding machine.

There is accordingly a need for a folding machine which is operationally reliable, even at high speeds in providing a division of the products stream after the folding blade cylinder, and which has a reduced dynamic loading and therefore wear of the means for controlling the folding blades.

According to the present invention there is provided a folding machine comprising a rotatable cylinder provided around its circumference with an even number of equidistantly spaced pairs of pivotable folding blades, the blades of each pair being arranged to respectively lead and trail in a given direction of rotation of the cylinder, a first rotatable cam for actuating the trailing blade of each of the blade pairs at and only at an article entraining station, a second rotatable cam for actuating the leading blade of one or each alternate one of the blade pairs at and only at a first article discharge station, a third rotatable cam for actuating the leading blade of the or each other one of the blade pairs at and only at a second discharge station which is selectably angularly spaced about the cylinder from the first discharge station, and drive means to rotate the cams and cylinder in the same rotational direction but at difference speeds in a ratio of the speed of the cams to the speed of the cylinder of 2:3 in the case of two blade pairs, 4:3 or 4:5 in the case of four blade pairs, and 6:5 or 6:7 in the case of six blade pairs, each of the 'cams having three equidistantly spaced blade actuating zones in the case of two blade pairs, three or five such zones in the case of four blade pairs and five or seven such zones in the case of six blade pairs, and the second and third cams being so rotationally staggered relative to each other that each actuating zone of one of the cams is disposed ahead of or behind a respective actuating zone of the other cam with respect to the rotational direction depending on whether the cams are rotated slower or faster than the cylinder and is angularly spaced from that actuating zone of the other cam by an angle determined by the angular spacing of the discharge stations divided by the number of actuating zones or each cam.

This arrangement makes possible, in a folding blade cylinder with an even number of blade pairs, a product discharge at two positions which can be established as desired within the scope of the spatial relationships within the folding machine. As a result, a reliable division of the product flow is possible.

For onward conveying of the two streams of discharged products there can be provided two belt conveyors associated in an optimum manner with a switch, so that the guiding of the products in this region is improved. Due to the higher functional reliabiiity, the output the folding machine can be increased and access to the switches can be improved. The two streams of products can each be fed by the belt conveyors to a device for the third fold operating at reduced speed.

As a further advantage with continuously rotating cams, the relative speed between the cams and, for example, cam rollers running thereon may be reduced. Favourable conditions are thus obtained for an increased output as a consequence of reduction in dynamic loading of the cams and associated components controlling the folding blades. Thus any gear mechanism used to drive the cams may be subjected to considerably less wear. Moreover, noise produced by cam rollers may be reduced.

Thus, with respect to the afore-mentioned speed ratios between the cams and the cylinder, the speed of associated cam rollers in the case of two blade pairs is 1/3, in the case of four blade pairs 1/3 or 1/5, and in the case of six blade pairs 1/5 or 1/7, of the speed of a cam roller running on a fixed cam.

The folding machine may advantageously be used when different printed products are to be separately discharged after the second fold (first transverse fold), possibly for receiving a third fold.

For varying the positions of the two product discharge stations, it is favourable if the two cams for actuating the leading blades are disposed adjacent to each other on a shaft of the cylinder and can be rotated relative to each other and fixed in a desired setting by threaded fastening elements or the like.

As a result, the angle of rotational staggering of the second and third cams can be correspondingly varied as a function of the relationship of the two stations for the product discharge.

The varying of the positions for the product discharge stations offers significant advantages for a product conversion in a folding machine embodying this invention, the conversion requiring relatively little expenditure, or for subsequent conversion of a conventional folding machine where the production conditions are changed, due to the high degree of adaptability to the available space conditions.

Preferably, for drive of the cams, cylinder, and an associated folding knife cylinder, a drive input gear engages a first gear wheel coupled by way of a shaft with a first cylindrical body of the folding knife cylinder which carries sheet guide elements. The first gear also drives the cams by way of a plurality of intermediate wheels, two of which are disposed one at each end of the folding blade cylinder and are connected together by a shaft. A second gear, which is of the same size as the first gear but has oblique teeth of opposite inclination, is coupled through a gear with the folding blade cylinder and through a hollow shaft with a second cylindrical body, carrying folding knives, of the folding knife cylinder, the hollow shaft housing the first-mentioned shaft.Both the first and second gears engage an axially displaceable double gear, the two sets of teeth of which each have a tooth inclination adapted to that of the teeth of the respective one of the first and second gears.

This form of drive offers the advantage that a folding adjustment, i.e. the rotation of the second cylindrical body with the folding knives and of the folding blade cylinder, relative to the first cylindrical body with the sheet guide elements, is possible without adjustment of '.he cams.

An embodiment of the present invention will now be more particularly described by way of example and with reference to the accompanying drawings, in which: Fig. 1 is a schematic longitudinal sectional view, along the line D-D of Fig. 4, of a folding blade cylinder, and associated cams and cam drives, of a folding machine according to the said embodiment, Fig. 2 is a view analogous to Fig. 1 along the line E-E of Fig. 4, Fig. 3 is a schematic longitudinal sectional view of a folding knife cylinder and of its drive connection to the folding blade cylinder, of the folding machine, and Fig.4 is a schematic end view of the folding blade cylinder of the folding machine, the cylinder having four folding blade pairs.

Referring now to the drawings, there is shown in Figs. 1 and 2 part of a folding machine comprising a folding blade cylinder 1 mounted on a shaft 2 which is rotatably mounted in two side walls 3 and 4 of the machine. The cylinder is provided around its circumference with four equidistantly spaced pairs I, II, Ill and IV (Fig. 4) of pivotable sheet folding blades 8 and 11 or 12, wherein the blades 11 and 12 are arranged to lead, and the blades 8 to trail, in the direction of rotation of the cylinder as indicated by the arrow in Fig. 4.

Rotatably mounted on the shaft 2 adjacent the ends of the cylinder 1 are two gear wheels 5 and 6.

The gear wheel 5 mounted on the right side is firmly bolted to a cam disc 7 for controlling the trailing blades 8, which are actuated exclusively at a product entraining station A (Fig. 4). The gear wheel 6 disposed on the left side is firmly bolted to two cam discs 9 and 10, which are capable of being rotated relative to each other and locked in a desired relative setting, for controlling the leading blades 11 and 12, respectively, which are actuated exclusively at product discharge stations B and C (Fig. 4).

Each of the blades 8 is rigidly connected to a respective arm 1 3 carrying a rotatable roller 1 6, each of the blades 11 to a respective arm 14 carrying a rotatable roller 17, and each of the blades 12 a respective arm 1 5 carrying a rotatable roller 1 8.

From Fig. 4 it can be seen that the leading blades 11 and 12 are associated, in respect of their sequence around the perimeter of the cylinder 1 , alternatively with the cam tracks 1 9 and 20 of the cam discs 9 and 1 0, so that all of the rollers 1 7 of the blades 11 actuated for product discharge at the station C run on the cam track 1 9, identified by a solid line in Fig. 4, of the cam disc 9, and all the rollers 1 8 of the blades 12 actuated for the same purpose at the station B run on the cam track 20, identified by a dot-and-dash line in Fig. 4 of the cam disc 10.

The cam 7 for controlling the trailing blades 8 has a cam track 21 formed by a groove 22 (Figs. 1 and 2) in which the corresponding rollers 1 6 are engaged.

In Figs. 1 and 2, for the sake of clarity, the arms 13, 14 and 1 5 are illustrated in a rotated position and thus the rollers 16, 17 and 18 are out of contact with the cam discs 7, 9 and 10.

The gear wheels 5 and 6 mesh with two intermediate gear wheels 23 and 24, respectively, which are mounted together on a shaft 25 passing right through and rotatably monted in the side wails 3 and 4 of the folding machine.

The intermediate gear wheel 23 is in engagement, via two further intermediate gear wheels 26 and 27 (Figs. 1 and 2), with a gear wheel 32 fixed on a shaft 28, which extends from the side wall 3 to the side wall 4 and carries a cylindrical body 30 of a folding knife cylinder 31, the body 30 carrying sheet guide elements 29. The gear wheel 32 is driven by a gear wheel 33 of a drive for the folding machine.

Rotatably mounted on the shaft 28 is a hollow shaft 34 which is journalled in the side wall 3 and which carries a cylindrical body 36 of the cylinder 31 , the body 36 carrying folding knives 35. Mounted on one end of the shaft 34 is a gear wheel 37 of the same size as the gear wheel 32 but having inclined teeth of opposite slope (Fig. 3). The two coaxially arranged gear wheels 32 and 37 mesh corresponding sets of teeth 38 and 39, respectively, of a double gear 40 (Fig. 3). The gear 40 is mounted on a shaft 41 journalled in the side wails 3 and can be axially displaced via an entraining device 42 by means of a threaded bolt 45 provided at one end with a handwheel 44 and guided in a hood 43 bolted to the side wall 3. The sets of teeth 38 and 39 each have a tooth inclination to suit that of the respective one of the gear wheels 32 and 37.Arranged between the hood 43 and handwheel 44 is a threaded lock ring 47, which is equipped with a hand lever 46 and serves to prevent undesired rotation of the bolt 45.

The gear wheel 37 also engages a gear wheel 48 fixed on the shaft 2 for driving the cylinder 1.

As previously mentioned and as shown in Fig. 4, the cylinder 1 has four blade pairs 1 to IV displaced at 900 from one another. The cam discs 7, 9 and 10 rotate in a speed ratio of 4:3 to the cylinder 1. For this purpose, the gear wheels which provide the drive connection between the cylinder 1 and the cam discs have the appropriate size relationships.

The cam tracks 10, 20 and 21 each have three actuating zones 55, 56 and 57, respectively, disposed at uniform intervals, i.e. spaced apart by 1200. Each zone 55 has a rise 49 and a fall 52, each zone 56 a rise 50 and a fall 53, and each zone 57 a rise 51 and a fall 54.

As shown in Fig. 4, the two positions for the product discharge stations B and C are offset by the angle P. In order that the leading blade 11 of each of the blade pairs I and Ill shall be opened for product discharge by the cam track 1 9 at the station C and leading blade 12 of the blade pairs Il and IV opened for product discharge by the cam track 20 at the station B, the cam tracks 19 and 20 must.pe rotationally staggered relative to each other, having regard to the number b of actuating zones 55 or 56 respectively per cam track, through the angle a in accordance with the equation a- b in the present embodiment a- 3 and must be fixed in this relationship.

In general, the two cam discs for actuating the leading blades must be rotationally staggered by the angle a relative to each other in opposition to their rotational direction when the cams rotate more' rapidly than the cylinder 1, as in the case of the present embodiment, and in their direction of rotation 'when the cam discs rotate more slowly than the cylinder.

The cam disc 7 so set so that in each case the product take-over from the folding knife cylinder 31 by the blade pairs I to IV takes place at the station A with simultaneous transverse folding of each product through cooperation of the folding knife 35 with the blades 8 and 11 or 8 and 12, respectively, of the cylinder 1, whereby only the previously opened trailing blade 8 is actuated, i.e. closed, so as to engage the product, while the respective. leading blade 11 or 12 remains closed during this procedure.

On the other hand, for the purpose of product discharge at the station C, only the leading blade 11 of the blade pairs I and Ill, and at the station B the leading blade 12 of the blade pairs II and IV, are opened, while the trailing blades 8 of blade pairs I to IV remain closed at the discharge stations. At the product take-over, the roller 1 6 for actuating each blade 8 is situated in the lower part of an actuating zone 57 bf the cam track 21 and the rollers 1 7 and 1 8 for actuating the blades 11 and 12, respectively, are situated in the upper parts 58 and 59, respectively, of their cam tracks.For product discharge at the station C with the blade 11 opened, the associated roller 1 7 is situated in the lower part of an actuating zone 55 and the roller 1 6 holding the associated blade 8 closed in the upper part 60 of the cam track 21. In a similar manner, for the purpose of product discharge at the station B, only the blade 12 is open, i.e. the roller 18 is situated in the lower part of an actuating zones 56 of the cam track 20.

In Fig. 4 it is shown how, at the station A, a product is transferred, with simultaneous transverse folding, from the folding knife cylinder 31 to the folding blade pair I of the folding blade cylinder 1, while at the station C of a folded product is discharged from the blade pair Ill to a belt conveyor 61. The blade pair II holds a product to be delivered at station B to a belt conveyor 62, whereas the blade pair IV has already discharged a product at the station B. The blade pairs I and Ill thus always discharge their products at the station C and the blade pairs II and IV at the station B.

In collected production, all the products are discharged either at the station B or at the station C, depending upon which sections of the folding knife cylinder 31 functioning as a collecting cylinder ate doubly loaded.

For the product discharge, the upper belt conveyor 62 has a controlled guide tongue 64 and the lower belt conveyor 61 an uncontrolled guide tongue 63. The bait conveyors are each coupled to, for example, a third folding device (not shown).

The drive illustrated in figs. 1 to 3 for the folding blade cylinder 1 and folding knife cylinder 31 offers the advantage that a fold adjustment, which is carried out with means not described in more detail, can take place independently of the drive for the cam discs 7, 9 and 1 0. For this purpose, after the lock ring 47 has been loosened, the gear 40 is axielly displaced by the handwheel 44.As a consequence of the previously described slope relationships, indicated symbolically by a circle in each of Figs. 1 to 3, of the inclined sets of teeth of the gear wheels 32 and 37 and the gear 40, the position or the gear wheel 32, including the cylinder body 30 and the drive connected to the gear wheel 32 for the cam discs 7, 9 and 10, remains unchanged through the intermediate gear wheels, 27, 26, 23 and 24, whereas the gear wheels 37, including the cylinder body 36 and also the gear wheel 48 for the drive of the cylinder 1; are rotationally offset by the corresponding amount.

As a departure from the arrangement shown in Figs. 1 to 3, the cam discs 7, 9 and 10 can be driven directly from the folding machine drive via spur gear or bevel gear steps.

The angle P between the station B and C for the product discharge can be varied as desired by rotationally displacing the two cam discs 9 and 10 relative to each other, after the screw connections have been released, through an appropriate angle a in accordance with the afore-mentioned equation a-- 3 and in the above-mentioned manner.

The two positions for the stations B and C can also be displaced together while retaining a specific angle iB between them. For this purpose, after the screw connections have been released, the cam discs 9 and 10 must be rotated together relative to the gear wheel 6.

The relationships illustrated in figs. 1 to 4 can be utilised in a folding blade cylinder equipped with a different even number of blade pairs. The table gives a summary for common applications of the machine.

Number of Speed ratio of Angle for the Folding blade actuation zones cam disc: folding rotational staggering pairs per cam blade cylinder of the actuation zones p 5 3 4:5 5 6

Claims (10)

1. A folding machine comprising a rotatable cylinder provided around its circumference with an even number of equidistantly spaced pairs of pivotable folding blades, the blades of each pair being arranged to respectively lead and trail in a given direction of rotation of the cylinder, a first rotatable cam for actuating the trailing blade of each of the blade pairs at and only at an article entraining station, a second rotatable cam for actuating the leading blade of one or each alternate one of the blade pairs at and only at a first article discharge station, a third rotatable cam for actuating the leading blade of the or each other one of the blade pairs at and only at a second discharge station which is selectably angularly spaced about the cylinder from the first discharge station, and drive means to rotate the cams and cylinder in the same rotational direction but at different speeds in a ratio of the speed of the cams to the speed of the cylinder of 2:3 in the case of two blade pairs, 4:3 or 4:5 in the case of four blade pairs, and 6:5 or 6::7 in the case of six blade pairs, each of the cams having three equidistantly spaced blade actuating zones in the case of two blade pairs, three or five such zones in the case of four blade pairs and five or seven such zones in the case of six blade pairs, and the second and third cams being so rotationally staggered relative to each other that each actuating zone of one of the cams is disposed ahead of or behind a respective actuating zone of the other cam with respect to the rotational direction depending on whether the cams are rotated slower or faster than the cylinder and is angularly spaced from that actuating zone of the other cam by an angle determined by the angular spacing of the discharge stations divided by the number of actuating zones of each cam.

2. A machine as claimed in claim 1, wherein each of the actuating zones in each cam comprises a respective fall and rise in a cam track.

3. A machine as claimed in either claim 1 or claim 2, wherein the second and third cams are disposed adjacent to each other on a shaft supporting the cylinder and are secured together in a selectable rotational position relative to each other.

4. A machine as claimed in any one of the preceding claims, comprising a folding knife cylinder with first and second cylindrical bodies which are provided with, respectively, sheet guide elements and folding knife elements and which are connected to be driven by the drive means.

5. A machine as claimed in claim 4, wherein the drive means comprises a first helical gear drivingly coupled to the cams and to said first cylindrical body, a second helical gear drivingly coupled to said second cylindrical body and to the cylinder with the folding blades, the helical gears being of the same diameter and being constructed and arranged so that the teeth of one of the gears are inclined in the opposite direction to the teeth of the other gear, and an axially displaceable coupling gear provided with two sets of teeth each mashed with and having a tooth inclination corresponding to that of the teeth of a respective one of the helical gears.

6. A machine as claimed in claim 5, wherein the second helical gear is coupled to the second cylindrical body by way of a hollow drive shaft and the first helical gear is coupled to the first cylindrical body by way of a drive shaft extenting in the hpllow drive shaft.

7. A machine as claimed in either claim 5 or claim 6, wherein the first helical gear is coupled to the cams by way of at least two intermediate gears arranged one adjacent each end of the cylinder with the folding blades.

8. A machine as claimed in any one of claims 5 to 7, wherein the second helical gear is coupled ato the cylinder with the folding blades by way of an intermediate gear.

9. A machine as claimed in any one of claims 5 to 8, further comprising a drive input engaging the first helical gear of the drive means.

10. A folding machine substantially as hereinbefore described with reference to the accompanying -drawings.