CA2089828C

CA2089828C - Gripper for a conveying device for conveying single-sheet or multiple-sheet printed products

Info

Publication number: CA2089828C
Application number: CA002089828A
Authority: CA
Inventors: Bruno Weber; Jurg Eberle
Original assignee: Ferag AG
Current assignee: Ferag AG
Priority date: 1992-02-19
Filing date: 1993-02-18
Publication date: 1999-02-16
Anticipated expiration: 2013-02-18
Also published as: NO180163B; AU3317193A; ES2089587T3; KR970009256B1; NZ245924A; KR930017793A; GR3020353T3; NO930540L; ATE138043T1; EP0557679B1; DE59302543D1; BR9300608A; NO180163C; EP0557679A1; FI930715A0; FI930715A7; NO930540D0; FI105673B; CA2089828A1; JPH0784271B2

Abstract

The two gripper parts (5, 6) of a gripper are mounted so as to be pivotable on a shaft (12) which, in turn, is mounted rotatably in a holder (13). Connected to this shaft (12) so as to be fixed against rotation is closing lever which bears at its end a follower roller which interacts with fixed closing links.
Furthermore, a resting part (16) for a compression spring (18) is connected to the shaft (12) via a spreader ring (17) so as to be fixed against rotation.
This compression spring (18) is supported at its other end on a bearing part (5) which is integral with the one gripper part (5). A pivot movement of the closing lever results in a corresponding clockwise pivoting of the resting part (16), as a result of which pivoting of the one gripper part (5) into the clamping position is brought about via the compression spring (18). This one gripper part (5) is blocked in its clamping position in which the compression spring (18) is compressed and exerts a corresponding clamping force.

Description

f~d 2 8 Grip~er for a conveying device for conveying single-sheet or multiple-sheet Printed ~roducts The present invention relates to a gripper for a conveying device for conveying single-sheet or multiple-sheet printed products, such as newspapers, magazines and parts thereof, according to Claim 1.
Preferred further developments of the gripper according to the invention form the subject-matter of the dependent claims.
Exemplary embodiments of the subject-matter of the invention are explained in detail below with refer-ence to the purely diagrammatical drawing, in which:
Figure 1 shows a lateral view of a conveying device for carrying printed products away in the transfer region, Figures 2 and 3 show a gripper of the conveying device according to Figure 1 in the open and closed states respectively,~0 Figure 4 shows a plan view of a gripper according to Figures 2 and 3, partially in section along the line IV-IV in Figure 5, Figure 5 shows a section along the line V-V in Figure 4, Figure 6 shows a lateral view of the gripper in the direction of the arrow A in Figure 4, Figures 7 and 8 show a gripper in an illustration corresponding to Figures 2 and 3 in a different pivot position in the open and closed states respectively, and Figures 9-12 show different conveying devices with a different arrangement of the grippers.
Figure 1 shows the transfer region of a convey-ing device 1 which has grippers 2 which are fastened at regular intervals to a continuous link chain (not shown) guided in a chain duct 3. Said link chain is guided over a deflection wheel 4 in the transfer region. The grippers 2 move in the direction of the arrow B along a closed circulation path.
Each gripper 2, whose construction and mode of functioning will be described in detail with reference to Figures 2-6, has a first gripper part 5 and a second gripper part 6. In the opened state of the grippers 2, the two gripper parts 5, 6 define a gripper opening 7 which faces towards the rear relative to the conveying direction B in the conveying device according to Figure 10 1.
Each gripper 2 grips a printed product 8 at its leading edge 8a (fold edge). The printed products 8 are fed in the direction of the arrow C by a belt conveyor 9 in a manner known per se in an imbricated formation S. As can be seen in Figure 1, each printed product lies in this imbricated formation S on the preceding printed product 8. A pressure roller 10 lies loosely on the printed products 8 fed by the belt conveyor 9.
The construction of the grippers 2 is now explained in detail below with reference to Figures 2-4.
The second gripper part 6 is of integral con-struction with a bearing part 11 which is mounted so as to be pivotable on a shaft 12 whose longitudinal axis is denoted by 12'. As emerges, in particular, from Figures 5 and 6, this shaft 12 is provided with longi-tudinal grooYes. The shaft 12 is mounted rotatably in a holder 13 which is U-shaped in cross-section and is fastened to a link chain 13 which is guided in the guide duct already mentioned. This link chain 14 is of known design and is very similar to the link chain such as is described, for example, in DE-A-2,629,528 or the corresponding document US-A-4,294,345. Figure 4 shows in each case half of a link chain 14 of a lighter con-struction and of a link chain 14' of heavierconstruction.
The first gripper part 5 is likewise of integral construction with a bearing part 15 which is arranged inside the holder 13 and i8 mounted so as to be pivotable on the shaft 12. The longitudinal axis 12' of this shaft 12 thus forms the common pivot axis for the bearing parts 11, 15 and thus for the gripper parts 6 and 5. A resting part 16 is connected to the shaft 12 so as to' be fixed against rotation, specifically via a spreader ring 17 which is integral with the resting part 16 and engages with projections in the longitu-dinal grooves of the shaft 12 (Figure 5). Supported on the resting part 16 is a compression spring 18 which is supported at the other end on a journal 19 which is inserted in the bearing part 15 for the first gripper part 5. As can readily be seen in Figure 5, a rotary movement of the shaft 12 in an anticlockwise rotary movement, i.e. in the direction of the arrow F, is transmitted via the compression spring 18 to the bear-ing part 15 and thus the first gripper part 5, which results in pivoting of the first gripper part 5 from the open position shown in Figures 2 and 5 into the clamping position illustrated in Figure 3.
Connected to the shaft 12 so as to be fixed against rotation is a closing lever 20 whose pivot axis 20' coincides with the longitudinal axis; 12' of the shaft 12. At its free end, the closing lever 20 bears a follower roller 21 which is freely rotatable about the axis of rotation 21'. The closing lever 20 is provided with a projecting blocking arm 22. The closing lever 20 is now arranged in such a way that the connecting line denoted by 23 between the pivot axi~3 20' and the axis of rotation 21' of the follower roller 21 runs trans-versely to the direction of movement B or B' of the grippers 2 (Figure 2). Furthermore, together with the plane D which is formed by the flat first gripper part 5, this connecting line 23 forms an angle ~ which i~
less than 90~ (Figure 2). This is important so that the first gripper part 5 can be moved from the open posi-tion into the clamping position during a movement in both directions of movement B and B'.
For blocking the first gripper part 5 in its clamping position, there is a locking device which has ~Y~2~

a locking lever 24 which is mounted on the bearing part 11 90 as to be pivotable about the axis 24'. This lock-ing lever 24 has at one end a blocking projection 25 which interacts with the blocking arm 22 on the closing lever 20 to lock the first gripper part 5, as is shown in Figure 3. The locking lever 24 is pivoted by means of a spring 26 into its blocking position and held therein. At the other end, the locking lever 24 has a follower roller 27 which is mounted so as to be freely rotatable about the axis of rotation 27'. In the block-ing position of the locking lever 24, the axis of rotation 27' of this follower roller 27 is flush with the longitudinal axis 12' of the shaft 12. It is ensured by this arrangement that release of the locking lever 24, i.e. pivoting into its release position by an unlocking force P acting on the follower roller 27 (Figure 3), is ensured in all pivot positions of the gripper 2.
Arranged on the bearing part 11 for the second gripper part 6 on the side opposite the locking lever 24 is a positioning follower roller 28 which is mounted so as to be freely rotatable about the axis 28'. In this case, the axis of rotation 28' is flush with the pivot axis 24' of the locking lever 24. The positioning follower roller 28 interacts with positioning links 29, by means of which the pivot position of the second gripper part 6 and thus of the open and closed gripper 2 is- defined. This second gripper part 6 is pivotable between two end positions which enclose with one another an angle of about 90~. One end position of the second gripper part 6 is illustrated in Figures 2 and 3, in which this second gripper part 6 runs approxi-mately in the direction of movement B, B' of the grippers 2. In the other end position shown in Figures 7 and 8, the second gripper part 6 extends approxi-mately perpendicular to the direction of movement B, B' of the grippers 2. By means of these end positions of the second gripper part 6, the end positions of the open and closed gripper are also defined, which gripper can assume any intermediate position depending on the design of the positioning links 29. It should also be mentioned in this context that the second gripper part 6 defining a plane E (Figure 2) is offset relative to the common pivot axis 12' of the two gripper parts 5, 6. In other words, the said plane E runs with spacing from this common pivot axis 12', as can readily be seen in Figure 2.
For closing the grippers 2, there are fixed closing links 30 which act on the follower roller 21 of the closing lever 20 and bring about pivoting of the latter in the closing direction, i.e. anticlockwise in the illustration according to Figure 2. These closing links 30 can be constructed in a manner known per se to correspond to the particular requirements. These clos-ing links 30 are illustrated only diagrammatically in the figures.
With reference to the closing links indicated by 30a and 30b in Figure 2, it is to be made clear that the gripper 2 can be closed in both conveying direc-tions B and B' by virtue of the arrangement and con-struction of the closing lever 20 described above. If the gripper is moved in the direction of the arrow B, the closing link 30a is to be provided. If, in con-trast, the gripper 2 is moved in the opposite direction B', the closing link is to be constructed as indicated by 30b.
The mode of functioning of the gripper 2 is now explained below with reference to Figures 2 and 3.
Prior to closing the gripper 2, the latter, i.e. the second gripper part 6, is moved by the posi-tioning link 29 into the desired product-receiving position and held therein (Figure 2). To pivot the first gripper part from the open position into the clamping position, the closing link 30 (30a or 30b respectively) begins to act on the follower roller 21 on the closing lever 20 which is thus pivoted anti-clockwise. This results in a corresponding rotation of the shaft 12 and thus also of the resting part 16. This ~8~.2~

rotary movement of the resting part 16 is transmitted via the compression spring 18 to the bearing part 15 of the first gripper part 5, as a result of which the latter is pivoted towards the clamping position. When the closing lever 20 has now reached a position denoted by the connecting line 23a in Figure 3, 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 closing lever 20, the blocking arm 22 also already begins to run up against the blocking projection 25 of the locking lever 24. When the closing lever 20 is rotated further, the locking lever 24 is now pressed back out of the blocking position by the blocking arm 22, continuing to act on the blocking pro-jection 25, counter to the force of the spring 26, i.e.
is pivoted anticlockwise. When the closing lever 20 has now reached its end position denoted by the connecting line 23 in Figure 3, locking of the closing lever 20 is effected by the blocking projection 25 of the locking lever 24 acting on the blocking arm 22. This means that, for locking the first gripper part 5 in its clamping position, the closing lever 20 has to travel only a short way which is illustrated in Figure 3 by the pivot angle ~. During the pivoting of the closing lever 20 through the abovementioned angle ~, the com-pression spring 18 is compressed, which obviously results in the clamping force exerted by the first gripper part 5 being increased accordingly. The magni-tude of this clamping force also depends on the thick-ness of the printed product 8 clamped between the gripper parts 5, 6.
The short pivot path (angle ~), as mentioned, which the closing lever 20 has to travel until it is locked, is possible because the compression spring 18 already exerts a clamping force, as already mentioned, as soon as the first gripper part 5 comes into contact with the second gripper part 6 or with the printed - 7 _ ~ 2 ~
product 8 to be gripped which has run into the gripper opening 7.
To unlock the closing lever 2 0 and thus the first 5 gripper part 5, i.e. to open the gripper 2, an opening arrangement comprising fixed opening links (not shown in Fig. 3) is provided which acts on the follower roller 27 of the locking lever 24 thus exerting an unlocking force P on the follower roller 27, causing the locking lever 24 to be pivoted anticlockwise. After a short pivot path (small pivot angle ~ in Figure 3), the blocking projection 25 is released from the blocking arm 22 on the closing lever 20 which is pivoted clockwise under the effect of the compression spring 18 becoming relaxed. As soon as the 15 blocking arm 22 is outside the range of action of the blocking projection 25 and the unlocking force no longer acts on the follower roller 27, the locking lever 24 is pivoted back into its blocking position again by the spring 26.
In illustrations corresponding to Figures 2 and 3, Figures 7 and 8 show a gripper 2 in the other end position in which the second gripper part 6 runs approximately perpendicular to the direction of movement B, B' of the gripper 2. The gripper 2 is moved into this end position 25 by a correspondingly constructed positioning link 29 which differs in construction from the positioning link 29 in Figures 2 and 3. Figure 7 shows the first gripper part 5 in its extreme open position in which it is held by a holding-open link 31 which interacts with the follower roller 21 on the closing lever 20.
The closing, locking and opening of the gripper 2 are effected in the end position illustrated in Figures 7 and 8 in the same manner as described with reference to Figures 2 and 3, in which case, however, the different links must 35 be constructed accordingly, as mentioned.
It can be seen by comparing Figures 2 and 3 with Figures 7 and 8 that the grippers 2 can be opened and closed in both end positions and thus also in any intermediate position, specifically irrespective to whether they are moved in the direction of the arrow B or in the direction of the arrow B'.
With reference to Figures 9-12, different possibilities of use of the grippers 2 are now described, as have been explained in conjunction with Figures 1-8.
In the embodiment according to Figure 9, the printed products 8 are brought in a suspended position by a feed conveyor 32 and are taken over and conveyed further by a delivery conveyer 33. As described with reference to Figures 7 and 8, the grippers 2 of the feed conveyor 32 are held by positioning links 29 in an end position in which the second gripper part 6 runs approximately perpendicular to the conveying direction approximately perpendicular to the conveying direction G of the feed conveyor 32. The grippers 2 of the delivery conveyor 3, which are moved in the same direction G, are likewise 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 region of their one edge 8a by the grippers 2 of the feed conveyor 32 are gripped at the opposite edge 8b by the grippers 2 of the delivery conveyor 3. As soon as the printed products 8 are clamped in the grippers 2 of the delivery 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 locking device 24, 25, the first gripper part 5 and the stationary opening arrangement 34, 35 can be referred to, in general terms, as "a locking device for blocking the first gripper part in its clamping position, the locking device being releasable by a stationary opening arrangement along the path of travel of the gripper.
The embodiment according to Figure 10 is very similar to that according to Figure 9 and differs from the latter by a different position of the grippers 2 during transfer of the printed products 8. In the embodiment according to Figure 10, the gripper openings 7 are namely not directed downwards or upwards, but obliquely towards the rear in the feed conveyor 32 and obliquely towards the front in the delivery conveyor 33.
The embodiment shown in Figure 11 is related to a certain extent to the embodiment according to Figure g 1. ~owever, in contrast to the variant according to Figure 1, the printed products 8 fed by the belt conveyor 9 in an imbricated formation S are not gripped at the leading edge 8a, but at the trailing edge 8b.
This requires a different position of the grippers 2 in the transfer region than in the embodiment shown in Figure 1. In Figure 11, 36 shows a guide for the printed products 8.
In the embodiment according to Figure 12 which is similar to that according to Figure 1, the belt con-veyor 9 brings the printed products 8 in an imbricated formation S' in which each printed product 8 lies on the following printed product. This means that the leading edges 8a of the printed products 8 lie at the bottom in the imbricated formation S'.
The printed products 8 are gripped by the con-veying device lb at this leading edge 8a. This means that the gripper openings 7 must point towards the rear in the transfer region.
It can readily be seen in Figure 1 and in Figures 9-12 that the same gripper construction as was described with reference to Figures 2-8 can be used for conveying devices 1, la, lb, 32, 33 with different tasks. By virtue of their special construction, the grippers 2 can be moved into different pivot positions and can be closed and opened satisfactorily in any pivot position without requiring constructive adapta-tions of the grippers 2 to the respective purpose. It is understood that the positioning links 29, the open-ing links 35 and any holding-open links 31 must be adapted to the particular purpose of the conveying devices. The corresponding links are indicated diagram-matically in Figures 9-12.
A further advantage of the gripper construction described is that the grippers 2 can be made and assembled in a simple manner. The two gripper parts 5 and 6, together with their bearing parts 11 and 15 respectively can be made of plastic, which results in a light construction. Since the closing force is -lo- ~U~ 28 primarily applied by the compression spring 18, the first gripper part 5 only has to have a limited flexi-bility. In order to secure the shaft 12 against dis-placement in the direction of its longitudinal axis 12', the shaft 12 is provided in the region of the spreader ring 17 with a circumferential groove in which a rib on the inside of the spreader ring 17 engages in the manner of a snap-on connection in the assembled state. This easy-assembly solution obviates the need for mounting separate securing rings or the like.
It is also conceivable to connect the first gripper part 5 to the shaft 12 directly via a spring element which bears 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 bearing part for the first gripper part 5 and the closing spring which is stressed when the gripper is closed. Such an embodiment is described, for example, in DE-A-3,102,242 and the corresponding document US-A-4,381,056.
Instead of fastening the grippers 2 at fixed intervals on a link chain 14, as shown with reference to Figure 4, it is also possible to mount them on bear-ing elements which, though coupled to one another, can be varied, however, in their spacing. Such a solution with bearing elements which can be varied in their spacing is described, for example, in EP-A-0,323,557 and the corresponding document US-A-5,007,629.

Claims

1. A gripper for a conveying device for conveying single-sheet or multiple-sheet printed products, such as newspapers, magazines and parts thereof, comprising:
a) a first gripper part and a second gripper part which can be moved relative to one another, the first gripper part being mounted to pivot about a pivot axis such that it can be pivoted from an open position to a clamping position in which it interacts with the second gripper part to clamp a printed product under a spring force;
b) a pivotably mounted closing lever which interacts with a fixed closing cam arranged along the path of travel of the gripper to pivot the first gripper part into the clamping position;
c) a locking device for blocking the first gripper part in its clamping position, the locking device being releasable by a stationary opening arrangement along the path of travel of the gripper, d) a further gripper part which is coupled to the closing lever for common pivotal movement with the closing lever; and e) a spring element which is arranged between the first gripper part and the further gripper part which is coupled with the closing lever for common pivotal movement, the spring element being tensioned during the closing movement of the gripper, the spring element transmitting the pivot movement of the closing lever to the first gripper part, and the spring element generating the closing force when the first gripper part is blocked in its clamping positions.

2. The gripper according to claim 1 comprising a rotatably mounted shaft to which both the closing lever and the further gripper part are fixedly connected against rotation, and on which the first gripper part is pivotably mounted.

3. The gripper according to claim 2 wherein the further gripper part comprises a rest for one end of the spring element, and the spring element comprises a compression spring and acts with its other end on the first gripper part.

4. The gripper according to claim 3 comprising a bearing part connected to the first gripper part, wherein the other end of the compression spring bears on the bearing part.

5. The gripper according to claim 2 wherein the second gripper part is mounted so as to be pivotable on the rotatably mounted shaft whose longitudinal axis forms a common pivot axis of the two gripper parts.

6. The gripper according to claim 1 wherein the closing lever comprises a follower member which interacts with a fixed closing cam.

7. The gripper of claim 6 wherein the follower member comprises a roller rotatably mounted on the closing lever.

8. The gripper according to claim 4 comprising a positioning follower member coupled to the second gripper part which interacts with a fixed positioning link for holding the second gripper part in a particular position.

9. The gripper according to claim 8 wherein the positioning follower member comprises a rotatably mounted roller.

10. The gripper according to claim 2 wherein the locking device comprises a pivotably mounted locking lever which acts on the rotatably mounted shaft, to block the first gripper part in its clamping position, and which can be pivoted into a release position by an opening arrangement.

11. The gripper according to claim 2 wherein the locking device comprises a pivotably mounted locking lever which acts on a blocking part, which is fixed against rotation with the rotatably mounted shaft, to block the first gripper part in its clamping position, and which can be pivoted into a release position by an opening arrangement.

12. The gripper according to claim 11 wherein the blocking part is constructed as an arm which is integral with the locking gear.

13. The gripper according to claim 11 comprising a rotatably mounted roller provided on the locking lever such that an opening arrangement can be brought into action on the roller, and the axis of rotation of the roller running approximately coaxially with the pivot axis of the two gripper parts in the blocking position of the locking lever.

14. The gripper according to claim 11 wherein the axis of rotation of the positioning follower roller runs approximately coaxially with the pivot axisof the locking lever.