EP0557679B1 - Conveyor gripper for conveying printed products of one or more sheets - Google Patents

Abstract

The two gripper parts (5, 6) of a gripper are pivotably mounted on a shaft (12) which for its part is rotatably mounted in a mounting (13). A closing lever is connected in a rotationally fixed manner to this shaft (12), which closing lever bears at its end a follower roll which interacts with stationary closing links. A support part (16) for a compression spring (18) is further connected to the shaft (12) via an expanding ring (17) so as to be rotationally fixed. Said compression spring (18) is supported at its other end on a bearing part (15) which is in one piece with one gripper part (5). A pivot movement of the closing lever results in a corresponding pivoting of the support part (16) in the counterclockwise direction, effecting, via the compression spring (18), a pivoting of one gripper part (5) into the clamping position. This one gripper part (5) is locked in its clamping position in which the compression spring (18) is compressed and exerts a corresponding clamping force. <IMAGE>

Description

The present invention relates to a gripper for a conveyor device for conveying single or multi-sheet printed products, such as newspapers, magazines and parts thereof, according to the preamble of claim 1.

Such a gripper is known, for example, from GB-A-2 043 599 and consists there of two clamping jaws which are held in the clamping position by a clamping spring encompassing them. In order to open the gripper, a lever which is firmly connected to one clamping jaw is actuated, another lever which is firmly connected to the other clamping jaw being held against a stop. The two jaws are rotatably mounted on a common axis of rotation.

This gripper has the disadvantage, among other things, that a constant force has to be exerted in order to keep the gripper open.

The present invention is therefore based on the object of designing a gripper of the type mentioned at the outset in such a way that a clamping force which is adapted to the thickness of the printed product is generated when the gripper is closed.

This object is achieved by a gripper with the features of patent claim 1.

Preferred further developments of the gripper according to the invention form the subject of the dependent claims.

Figur 1

in Seitenansicht eine Fördereinrichtung zum Wegführen von Druckereierzeugnissen im Uebernahmebereich,

Fig. 2 u. 3

einen Greifer der Fördereinrichtung gemäss Figur 1 im offenen bzw. geschlossenen Zustand,

Fig.4

eine Greifer gemäss den Figuren 2 und 3 in Draufsicht und teilweise im Schnitt entlang der Linie IV -IV in Figur 5,

Fig.5

einen Schnitt entlang der Linie V - V in Fig. 4,

Fig.6

eine Seitenansicht des Greifers in Richtung des Pfeiles A in Figur 4,

Fig. 7 u.8

in einer den Figuren 2 und 3 entsprechenden Darstellung einen Greifer in einer anderen Schwenklage im offenen bzw. geschlossenen Zustand, und

Fig. 9-12

verschiedene Fördereinrichtungen mit unterschiedlicher Anordnung der Greifer.

Exemplary embodiments of the subject matter of the invention are explained in more detail below with reference to the drawing. It shows purely schematically:

Figure 1

a side view of a conveyor for taking away printed products in the takeover area,

Fig. 2 u. 3rd

1 a gripper of the conveyor device according to FIG. 1 in the open or closed state,

Fig. 4

2 a gripper according to FIGS. 2 and 3 in plan view and partly in section along line IV-IV in FIG. 5,

Fig. 5

3 shows a section along the line V - V in FIG. 4,

Fig. 6

3 shows a side view of the gripper in the direction of arrow A in FIG. 4,

7 and 8

in a representation corresponding to Figures 2 and 3, a gripper in a different pivot position in the open or closed state, and

Fig. 9-12

different conveyors with different gripper arrangements.

FIG. 1 shows the takeover area of a conveying device 1 which has grippers 2 which are attached at regular intervals to an endless link chain (not shown) which is guided in a chain channel 3. The latter is guided over a deflection wheel 4 in the takeover area. The grippers move in the direction of arrow B along a closed orbit.

Each gripper 2, the structure and mode of operation of which will be described in more detail with reference to FIGS. 2-6, has a first gripper part 5 and a second gripper part 6. In the open state of the grippers 2, the two gripper parts 5, 6 define a gripper opening 7, which in the conveying device according to FIG. 1 points backwards with respect to the conveying direction B.

Each gripper 2 grips a printed product 8 at its leading edge 8a (folded edge). The printed products 8 are fed in a manner known per se in a scale formation S by a belt conveyor 9 in the direction of arrow C. As can be seen from FIG. 1, each printed product rests on the preceding printed product 8 in this scale formation S. A pressure roller 10 lies loosely on the printed products 8 fed by the belt conveyor 9.

The structure of the grippers 2 is now explained in more detail below with reference to FIGS. 2-4.

The second gripper part 6 is formed in one piece with a support part 11 which is pivotally mounted on a shaft 12, the longitudinal axis of which is designated 12 '. As can be seen in particular from FIGS. 5 and 6, this shaft 12 is provided with longitudinal grooves. The shaft 12 is rotatably mounted in a cross-sectionally U-shaped holder 13 which is fastened to a link chain 13 which is guided in the guide channel 3 already mentioned. This link chain 14 is of a known type and is very similar to the link chain as described, for example, in DE-A-26 29 528 and the corresponding US-A-4,294,345. FIG. 4 shows half of a link chain 14 of a lighter design and one link chain 14 'of a heavier design.

The first gripper part 5 is also formed in one piece with a support part 15, which is arranged in the interior of the holder 13 and is pivotably mounted on the shaft 12. The longitudinal axis 12 'of this shaft 12 thus forms the common pivot axis for the support parts 11, 15 and thus for the gripper parts 6 and 5. A support part 16 is connected in a rotationally fixed manner to the shaft 12, specifically via an expansion ring 17 integral with the support part 16, which engages with projections in the longitudinal grooves of the shaft 12 (Figure 5). On the support part 16, a compression spring 18 is supported, which is supported at the other end on a pin 19 which is inserted into the support part 15 for the first gripper part 5. As is readily apparent from FIG. 5, a rotational movement of the shaft 12 in the counterclockwise direction, ie in the direction of the arrow F, is transmitted via the compression spring 18 to the support part 15 and thus to the first gripper part 5, which causes the first to pivot Gripper part 5 results from the open position shown in Figures 2 and 5 in the clamping position, which is shown in Figure 3.

A locking lever 20 is connected to the shaft 12 in a rotationally fixed manner, the pivot axis 20 'of which coincides with the longitudinal axis 12' of the shaft 12. At its free end, the closing lever 20 carries a follower roller 21 which can be freely rotated about the axis of rotation 21 '. The locking lever 20 is provided with a protruding locking arm 22. The locking lever 20 is now arranged such that the connecting line designated 23 between the pivot axis 20 'and the axis of rotation 21' of the follower roller 21 extends transversely to the direction of movement B or B 'of the grippers 2 (FIG. 2). Furthermore, this connecting line 23 forms with the plane D, which is formed by the flat first gripper part 5, an angle α which is less than 90 ° (FIG. 2). This is important so that the first gripper part 5 can be moved from the open position into the clamping position during a movement in both directions of movement B and B '.

To block the first gripper part 5 in its clamping position, a locking device is provided which has a locking lever 24 which is mounted on the support part 11 so as to be pivotable about the axis 24 '. This locking lever 24 has a locking lug 25 at one end, which cooperates with the locking arm 22 on the locking lever 20 to lock the first gripper part 5, as shown in FIG. 3. The locking lever 24 is pivoted into its locking position by means of a spring 26 and held in this. At the other end, the locking lever 24 carries a follower roller 27 which is freely rotatable about the axis of rotation 27 '. In the locked position of the locking lever 24, the Axis of rotation 27 'of this follower roller 27 with the longitudinal axis 12' of the shaft 12. This arrangement ensures that a release of the locking lever 24, ie a pivoting into its release position, by an unlocking force P acting on the follower roller 27 (FIG. 3), in all swivel positions of the gripper 2 is ensured.

A positioning follower roller 28 is arranged on the support part 11 for the second gripper part 6 on the side opposite the locking lever 24 and is freely rotatable about the axis 28 '. The axis of rotation 28 'is aligned with the pivot axis 24' of the locking lever 24. The positioning follower roller 28 interacts with positioning guides 29, by means of which the pivot position of the second gripper part 6 and thus of the open and closed gripper 2 is determined. This second gripper part 6 can be pivoted between two end positions, which together form an angle of approximately 90 °. One end position of the second gripper part 6 is shown in FIGS. 2 and 3, in which this second gripper part 6 extends approximately in the direction of movement B, B 'of the gripper 2. In the other end position, which is shown in FIGS. 7 and 8, the second gripper part 6 extends approximately at right angles to the direction of movement B, B 'of the grippers 2. These end positions of the second gripper part 6 also determine the end positions of the open and closed grippers which, depending on the design of the positioning link 29, can take any intermediate layer. In this connection it should also be mentioned that the second gripper part 6, which defines a plane E (FIG. 2), is offset with respect to the common pivot axis 12 'of the two gripper parts 5, 6. In other words, said plane E runs at a distance from this common pivot axis 12 ', as is readily apparent from FIG. 2.

To close the grippers 2 there are stationary locking links 30 which act on the follower roller 21 of the locking lever 20 and pivot the latter in the closing direction, i.e. 2 in the counterclockwise direction in the illustration according to FIG. These closing scenes 30 can be designed in a manner known per se to meet the respective requirements. These closing scenes 30 are shown only schematically in the figures.

2 to illustrate that, thanks to the arrangement and design of the closing lever 20 described above, the gripper 2 can be closed in both conveying directions B and B '. If the gripper moves in the direction of arrow B, the closing link 30a must be provided. If, on the other hand, the gripper 2 is moved in the opposite direction B ', the closing link is to be designed as indicated by 30b.

The operation of the gripper 2 will now be explained with reference to FIGS. 2 and 3.

Before the gripper 2 is closed, it, ie the second gripper part 6, is brought into the desired product receiving position by the positioning link 29 and held in this position (FIG. 2). To pivot the first gripper part from the open position into the clamping position, the closing link 30 (or 30a or 30b) acts on the follower roller 21 on the closing lever 20, which is thereby pivoted counterclockwise. This results in a corresponding rotation of the shaft 12 and thus also of the support part 16. This rotational movement of the support part 16 is transmitted via the compression spring 18 to the support part 15 of the first gripper part 5, whereby the latter is pivoted against the clamping position. If the closing lever 20 has now reached a position which is indicated in FIG. 3 by the connecting line 23a, the first gripper part 5 comes into contact with the second gripper part 6. In this position, the compression spring 18 already exerts a certain clamping force. In this position of the locking lever 20, the locking arm 22 begins to run onto the locking lug 25 of the locking lever 24. When the locking lever 20 is turned further, the locking lever 24 is now pushed back out of the locking position against the force of the spring 26 by the locking arm 22 which continues to act on the locking lug 25, that is to say pivoted counterclockwise. If the locking lever 20 has now reached its end position, which is denoted by the connecting line 23 in FIG. 3, the locking lever 20 is locked by the locking lug 25 of the locking lever 24 acting on the locking arm 22. This means that for locking the first gripper part 5 in its clamped position, the closing lever 20 only has to travel a small distance, which is shown in FIG. 3 by the pivot angle β. During the pivoting of the locking lever 20 by the mentioned angle β, the compression spring 18 is compressed, which obviously has the consequence that the clamping force exerted by the first gripper part 5 is increased accordingly. The magnitude of this clamping force also depends on the thickness of the printed product 8 clamped between the gripper parts 5, 6.

The short swivel path (angle β), which the closing lever 20 has to cover until it is locked, is possible because, as already mentioned, the compression spring 18 already exerts a clamping force as soon as the first gripper part 5 with the second gripper part 6 or with comes into contact with the printed product 8 that has entered the gripper opening 7 and is to be gripped.

To unlock the locking lever 20 and thus the first gripper part 5, i.e. to open the gripper 2, an unlocking force P is exerted on the follower roller 27 on the locking lever 24 by an opening arrangement, not shown in FIG. 3, which has the consequence that the locking lever 24 is pivoted counterclockwise. After a short swivel path (small swivel angle γ in FIG. 3), the locking lug 25 is released from the locking arm 22 on the closing lever 20, which is pivoted clockwise under the action of the relaxing compression spring 18. As soon as the locking arm 22 is outside the effective range of the locking lug 25 and the unlocking force no longer acts on the follower roller 27, the locking lever 24 is pivoted back into its locking position by the spring 26.

FIGS. 7 and 8 show a corresponding gripper 2 in the other end position in FIGS. 2 and 3, in which the second gripper part 6 extends approximately at right angles to the direction of movement B, B 'of the gripper 2. The gripper 2 is brought into this end position by a correspondingly configured positioning link 29, which is designed differently than the positioning link 29 in FIGS. 2 and 3. In FIG. 7, the first gripper part 5 is shown in its extreme open position, in which it is guided by a Hold open gate 31 is held, which cooperates with the follower roller 21 on the locking lever 20.

The closing, locking and opening of the gripper 2 takes place in the end position shown in FIGS. 7 and 8 in the same way as described with reference to FIGS. 2 and 3, but, as mentioned, the different scenes must be designed accordingly.

A comparison of FIGS. 2 and 3 with FIGS. 7 and 8 shows that the grippers 2 can be closed and opened in both end positions and thus also in any intermediate position, regardless of whether they are in the direction of arrow B or in the direction of arrow B 'are moved.

Various possible uses of the grippers 2, as have been explained in connection with FIGS. 1-8, will now be described with reference to FIGS. 9-12.

In the embodiment according to FIG. 9, the printed products 8 are fed in a hanging position by a feed conveyor 32 and taken over by a conveyor 33 and conveyed further. The grippers 2 of the feed conveyor 32 are held in an end position, as described with reference to FIGS. 7 and 8, by means of positioning links 29, in which the second gripper part 6 runs approximately at right angles to the conveying direction G of the feed conveyor 32. The grippers 2 of the conveyor 3, which are moved in the same direction G, are also held in this end position, but the gripper opening 7 is directed upwards and the second gripper part 6 forms the trailing part of the grippers 2.

The printed products 8 held in the area of their one edge 8a by the grippers 2 of the feed conveyor 32 are grasped on the opposite edge 8b by the grippers 2 of the removal conveyor 3. As soon as the printed products 8 are clamped in the grippers 2 of the removal conveyor 3, the grippers 2 of the feed conveyor 32 are opened by means of an opening arrangement 34 which has an opening link 35 which acts on the follower roller 27 on the locking lever 24.

The embodiment according to FIG. 10 is very similar to that according to FIG. 9 and differs from the latter by a different position of the grippers 2 when delivering or taking over the printed products 8. In the embodiment according to FIG. 10, the gripper openings 7 are not after directed downwards or upwards, but at the feed conveyor 32 obliquely to the rear and at the conveyor 33 at an angle to the front.

The embodiment shown in FIG. 11 is somewhat related to the embodiment according to FIG. 1. However, in contrast to the variant according to FIG. 1, the printed products 8 fed by the belt conveyor 9 in scale formation S are not detected on the leading edge 8a, but rather on the trailing edge 8b. This requires a different position of the grippers 2 in the takeover area than in the embodiment shown in FIG. 1. A guide for the printed products 8 is shown at 36 in FIG.

In the embodiment according to FIG. 12, which is similar to that according to FIG. 1, the belt conveyor 9 feeds the printed products 8 in a scale formation S ', in which each printed product 8 rests on the subsequent printed product. This means that the leading edges 8a of the printed products 8 lie at the bottom in the scale formation S '.

The printed products 8 are captured by the conveyor 1b at this leading edge 8a. This means that the gripper openings 7 must point to the rear in the takeover area.

It is readily apparent from FIGS. 1 and 9-12 that the same gripper construction as described with reference to FIGS. 2-8 can be used for conveying devices 1, 1b, 32, 33 with different tasks. Thanks to their special design, the grippers 2 can be brought into different swivel positions and can be closed and opened perfectly in any swivel position without the need to adapt the grippers 2 to the respective application. It goes without saying that the positioning links 29, the opening links 35 and any keeping-open links 31 must be adapted to the particular purpose of the conveying devices. The corresponding backdrops are indicated schematically in FIGS. 9-12.

Another advantage of the gripper construction described is that the grippers 2 can be manufactured and assembled in a simple manner. The two gripper parts 5 and 6 together with their supporting parts 11 and 15 can be made of plastic, which results in a lightweight construction. Since the closing force is primarily applied by the compression spring 18, the first gripper part 5 have only limited flexibility. In order to secure the shaft 2 against displacement in the direction of its longitudinal axis 12 ', the shaft 12 is provided in the region of the expansion ring 17 with a circumferential groove into which a rib engages in the manner of a snap connection on the inside of the expansion ring 17 in the assembled state. This installation-friendly solution makes it unnecessary to attach separate circlips or the like.

It is also conceivable to connect the first gripper part 5 directly to the shaft 12 via a spring element which carries the first gripper part 5 at one end and is connected to the shaft 12 at the other end. This spring element then forms both the supporting part for the first gripper part 5 and the closing spring which is tensioned when the gripper is closed. Such an embodiment is described for example in DE-A-31 02 242 and the corresponding US-A-4,381,056.

It is also possible to attach the grippers 2 to support elements which are coupled to one another, but whose distance can be changed, instead of being attached to a link chain 14 at fixed intervals as shown in FIG. 4. Such a solution with support elements that can be changed in their spacing is described, for example, in EP-A-0 323 557 and the corresponding US-A-5,007,629.

Claims (10)

1. A gripper for a conveying device for conveying single- or multiple-sheet printed products (8), such as newspapers, magazines and parts hereof, with two gripper parts (5, 6) movable relative to each other, of which at least the one, first gripper part (5) is swivellably mounted and in a clamping position under the action of a spring element (18) cooperates with the second gripper part (6) to firmly clamp a printed product (8), characterised by the following features:

   a) a swivellably mounted closing lever (20), which to swivel the first gripper part (5) from an open position into the clamping position is intended to cooperate with at least one fixed closing link.

   b) a locking device (24, 25) able to be released by means of fixed opening arangements (34), preferably links (35), to lock the first gripper part (5) in its clamping position (5),

   c) a bearing part (16) coupled to the closing lever (20) and swivelling together with the latter, and

   d) the spring element (18) is arranged between the bearing part (16) swivelling together with the closing lever (20), and the first gripper part (5) and, being tensile on closing of the gripper (2), transfers the swivelling movement of the closing lever (20) onto the first gripper part (5) and produces a closing force with the first gripper part (5) locked in its clamping position.
2. A gripper according to Claim 1, characterised by a rotatably mounted shaft (12) with which both the closing lever (20) and also the bearing part (16), swivelling together with the latter, are connected so as to be rotationally secure and on which the first gripper part (5) is swivellably mounted.
3. A gripper according to Claim 2, characterised in that the bearing part (16), swivelling together with the closing lever (20), is constructed as a support for the one end of the spring element (18), which is constructed as a compression spring, which acts with its other end on the first gripper part (5), preferably by bearing against a carrying part (15) connected with the first gripper part (5).
4. A gripper according to Claim 2 or 3, characterised in that the second gripper part (6) is swivellably mounted on the shaft (12) the longitudinal axis (12') of which forms the common swivel axis of the two gripper parts (5, 6).
5. A gripper according to one of Claims 1-4, characterised in that the closing lever (20) has a follower member (21), preferably a rotatably mounted roller, intended to cooperate with fixed closing links (30).
6. A gripper according to Claim 4 or 5, characterised by a positioning follower member (28), preferably a rotatably mounted roller, coupled to the second gripper part (6) and intended to cooperate with fixed positioning links (29) to hold the second gripper part (6) in a particular swivelled position.
7. A gripper according to one of Claims 2-6, characterised in that the locking device (24, 25) has a swivellably mounted locking lever (24), which for locking the first gripper part (5) in its clamping position acts on the shaft (12) or on a locking part (22) which is rotationally secure therewith, and which is swivellable into a releasing position through the opening arrangements (34), preferably against the force of a spring (26).
8. A gripper according to Claim 7, characterised in that the locking part (22) is consturcted as an arm in one piece with the closing lever (21).
9. A gripper according to Claim 7 or 8, characterised in that on the locking lever (24) a rotatably mounted roller (27) is provided, onto which the opening arrangements (34) are able to be brought into action and the rotation axis (27') of which in the locking position of the locking lever (24) preferably runs approximately coaxially to the swivel axis (12') of the two gripper parts (5, 6).
10. A gripper according to one of Claims 7-9, characterised in that the rotation axis (28') of the positioning follower roller (28) runs approximately coaxially to the swivel axis (24') of the locking lever (24).

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