FR2526710A1 - Serigraphic printing bottle conveyor - has endless chain in one or two planes to mount pincers gripping bottles by neck - Google Patents

Abstract

The serigraphic printing machine makes coloured impressions on bottles, using a double chain conveyor to move sidelong bottles along a prodn. line. The conveyor comprises a chain (8) equipped to take a localised grip on the bottles which travels in a horizontal plane past a series of operational postions (4,5,6). Alternatively the conveyor trajectory may occupy two planes, the chain drive wheels being sited in the immediate proximity of the posts and driven positively by the same driving member. Certain intermediate chain wheels rotate freely on axles equipped with tensioning gear. Handling is effected by laminar pincers gripping the thread of the neck (2a) of a bottle (2). The pincer grip allows bottle rotation and chain axle pins also serve as pincer arm fulcra.

Description

 The present invention relates to machines for printing objects which must receive a succession of operations. By way of example, the improvements according to the invention can be applied to a screen printing machine for printing in several colors of bottles.

 In known installations, the objects are transported in front of successive work stations by means of a double chain supporting receptacles of various shapes. These receptacles are sometimes produced in the form of nacelles whose inner faces are curved so that a cylindrical object touches these faces only at four points so that the ink does not smear the object when it has just entered. . In other cases, each of the chains supports a V-shaped part intended to support the two ends of the printed object.

 It is easily understood that the chains thus produced can only bend upwards or downwards so that the entire chain is necessarily located in a substantially vertical plane, so that the longitudinal axis of the objects is necessarily horizontal.

 In some machines the same conveyor passes in front of all the work stations, that is to say that each object is supported at the same place of the conveyor from the loading station to that of unloading. In other machines there are several chain sections; a first serves the first workstations, a second the following and so on; in this case the objects pass from one section to another by means of more or less complicated transfer devices.

 In one or other of these latter embodiments, the total length of the conveyor is important since certain working phases, such as that of drying in particular, require a fairly long time.

This obligation combined with the fact that the chain can only evolve in the vertical plane results in a large footprint for the production line. In this way the work stations are very far from each other so that it is difficult to actuate them by common control members and to monitor them easily.

 The improvements which are the subject of the present invention aim to remedy the above-mentioned drawbacks and to allow the production of a printing machine with multiple stations which responds better than so far to the various wishes of the practice.

 To this end, the conveyor of the machine according to the invention comprises a single chain capable of folding in two perpendicular planes and which supports means suitable for gripping each object by a single zone. This mode of gripping objects makes it possible to evolve the chain in planes other than the vertical plane, as is not the case with known carriers.

 Thanks to the invention, it is possible to bring the work stations closer together, which makes it possible to make certain control members common to several of them, mainly with regard to the synchronized drive of the chain at all work stations. In addition, this concentration of different workstations facilitates monitoring of the machine.

The appended drawing, given by way of example, will allow a better understanding of the invention, the characteristics which it presents and the advantages which it is capable of providing.
Fig. 1 is a very schematic general view of a printing machine comprising application of the improvements according to the invention.

 Fig. 2 is a view similar to that of FIG. 1 but illustrating a machine whose conveyor moves in two perpendicular planes, the printing of the objects being done when they are oriented vertically as in fig. 1.

 Fig. 3 is another alternative embodiment in which the conveyor moves in two perpendicular planes but in which the printing of the objects is done when they are oriented horizontally.

 Fig. 4 and 5 illustrate the manner in which each object is held along the conveyor by only one of its zones.

 Fig. 6 shows in plan view how the objects to be printed are brought to the loading station.

Fig. 7 is an elevation view with cutaway of the
Door.

 Fig. 8 illustrates a control variant of the devices for gripping objects.

 Fig. 9 shows a system making it possible to subject a rotation of 1800 to a bottle maintained by a device for gripping the transporter.

 The printing machine illustrated in fig. 1 comprises first of all a conveyor 1 intended to grip bottles 2 by their necks 2a from a loading station 3 in order to pass them successively to three printing stations 4, 5, 6 between which the bottles pass through an ink drying enclosure. At the end of the circuit, the printed bottles are evacuated to an unloading station 7.

 It will be noted that the conveyor 1 is produced by means of a chain 8 which passes around three drive wheels 9, 10, 11 arranged in close proximity to each printing station 4, 5, 6 and around return wheels 12, 13, 14 and 15, two of which 13 and 14 constitute a tensioner free from the action of a spring return system 16 so that the chain 8 is perfectly tensioned. The bottles 2, after the loading station, are brought to the printing station 4, then the chain enters an oven (not shown) intended to dry the ink, the chain strands located respectively between the wheels 9 and 13, 13 and 10 located in this oven. The bottles are then printed at the second printing station 5, then they enter a second oven through which pass the strands of chain located between the wheels 10 and 14, 14 and 11. At the level of the third drive wheel, the objects are printed by the third printing station 6, then the chain passes through a third oven located between the drive wheel 11 and those of return 15 and 12. The bottles are then unloaded on a conveyor belt located at unloading station 7, while a conveyor belt 17 is provided at loading station 3, as will be better explained below.

 Thanks to the position of the driving wheels 9, 10, 11 in the immediate vicinity of the three printing stations 4, 5, 6 it is ensured that in the areas close to said stations the position of the chain links is well defined. The length errors due to the imprecision of the pitch are compensated by the wheels mounted on tensioners which are arranged as illustrated in the drawing so that the chaste 8 always passes over a tensioning wheel between two driving wheels. We therefore obtain a precise position of the three bottles which must be printed simultaneously at the three printing stations 4, 5, 6. Each of the wheels 9, 10, 11 is wedged on a vertical shaft 18, 19, 20 respectively, said trees being supported by a single motor shaft 21 coupled to a drive means such as a geared motor 22. The transmission of the movement from the shaft 21 to those 18, 19, 20 can be effected by c8nical references 23.

 In order to reduce the horizontal dimensions of a machine such as that illustrated in fig. 1, provision is made to raise the chain strands located behind the unloading station 7c in a vertical plane. As many chain sprockets 24 oriented in a vertical plane are used as there are chain strands, said sprockets being madly mounted on a horizontal shaft 25.

 As illustrated in fig. 3 it is also possible to raise the front of the machine, that is to say arrange the printing stations in a horizontal plane by orienting the strands of chain located at the front of the loading station 3 in a vertical plane by means sprockets 26 oriented in the same way as those 24 and mounted on a horizontal shaft 27. One could also have all the strands of the chain 8 of the machine in a vertical plane while keeping the horizontal printing stations. To this end, the rear reference wheels referenced 12, 13, 14 and 15 would be brought into a vertical plane at 12 '13', 14 'and 15'.

 In other words, the conveyor chain of the machine according to the invention can be placed either in a horizontal plane, or in a vertical plane, or in two substantially perpendicular planes.

Of course, to carry out such an arrangement, it is necessary to use a chain capable of being articulated in two perpendicular planes such as that described in American patent 3,768,631.

 The channel 8 is provided with a multiplicity of gripping means produced in the form of pliers 28, one of which is illustrated in FIG. 4.

These pliers comprise, in the manner of a pair of scissors, two flat branches 29-30 each articulated with respect to two vertical pivots 31, 32 secured to the chain 8. The branches comprise two lugs 29a, 30a between which is arranged a spring pull 33 suitable for keeping the ends or jaws 29b, 30b intended to hold the neck 2a of a bottle 2 close together. The ends 29b, 30b in question are cut so as to constitute two notches 29c, 30c in the form of a V to improve the neck holding. In addition, the ends 29b, 30b of the two branches of each device 28 are returned and oriented obliquely so that the notches come to cooperate with the core of the neck between the projections of its thread.

 The rear ends of the branches 29 and 30 situated beyond the pivots 31, 32 with respect to the jaws 29h, 30b intersect and carry rollers 34, 35 against which a pusher intended to open the clamp comes to act.

 Illustrated in fig. 5 an alternative embodiment of one of the branches of the device 28. According to this variant the branch 29 carries a chute 36 in the form of a vertical axis which cooperates with the outside of the net when the device 28 grasps a neck 2a, while that the notch 30c of the other branch comes to bear against the core of the neck.

 Illustrated in fig. 6 a section of chalne 8 carrying three gripping devices 28 at the level of the loading station 3 for the bottles 2.

 Before this station the device is closed, that is to say that its branches 29, 30 are tightened due to the reaction of the spring 33. For this purpose there is provided on one of the branches a stop 37 which keeps them very slightly apart.

 When the chain arrives at the right of the loading station 3, a pusher 38 comes to act on the rollers 34, 35 of the branches in order to open them, then the pusher is withdrawn so that the branches close so that the bottle then is only retained by its neck.

 The loading station 3 comprises the conveyor belt 17 which moves continuously perpendicular to the chain strand in question. A fixed stop 39 is arranged across the belt 17 so as to stop the line of bottles that it moves. The top of the necks 2a of the bottles is located below the mean plane of the jaws of each gripping device 28 so that they can only pinch the neck if the bottle is raised by a plate 40 mounted at the end of the piston rod 41 of a jack not shown, said rod passing through the belt 17 which is in reality produced by means of two cortex bands spaced from one another. Of course bars 42 are placed on each side of the mat 17 so as to laterally guide the bottles.

 In a preferred embodiment illustrated in FIG. 8, the two branches 29 ′, 30 ′ of each device 28 could cross between the chain 8 and the jaws while still being articulated around the pivots 31, 32. At this moment the pusher 38 ′ would itself carry the rollers 43, 44 intended to cooperate with the internal faces of the parts of the arms opposite the jaws. Thus one would be assured of a good functioning of the rollers while in the other case illustrated in fig. 6 there is a risk of jamming of the rollers 34, 35 on their axes due to their passage in the ovens.

 In this case as in that of the embodiment of FIG. 6, the pivots 31, 32 could constitute the axes of the chain 8 or else these could be provided hollow and form a bearing for said pivots.

 Illustrated in fig. 9 how a bottle 2 ′ with rectangular cross section held by a gripping device 28 can be turned over 180 by means of a mandrel 45 suitable for enclosing its two external faces and another subjected to a rotational movement of 1800.

 A printing machine for vials has thus been produced which has a reduced bulk and whose gripping devices for the vials allow the orientation of the vials to be varied without loosening said gripping devices.

 In order to be able to adapt the gripping devices 28 to the different kinds of threading of the bottles, provision may be made for their jaws to be interchangeable.

 It should moreover be understood that the above description has been given only by way of example and that it in no way limits the field of the invention from which one would not depart by replacing the execution details described by all other equivalents. It goes without saying that other workstations can exist at any desired location in the chain, for example to pre-treat the flasks by flame, to dust them, to carry out power stations, etc.

Claims (10)

 1. Printing machine, in particular screen printing machine, intended to subject objects to a succession of operations at different work stations of the type comprising a double chain conveyor intended to convey the objects oriented horizontally from one station to another, characterized in that the conveyor consists of a single chain (8) comprising gripping devices (28) of objects by only one of their area, while said conveyor circulates in a horizontal plane and passes in front of the various work stations ( 4, 5, 6).  2. Printing machine, in particular screen printing, intended to subject objects to a succession of operations at different workstations of the kind comprising a double chain conveyor intended to convey objects oriented horizontally from one station to the other, characterized in that the conveyor is constituted by a single chain (8) comprising gripping devices (28) of objects by only one of their zone, while said conveyor circulates in two planes and passes in front of the various work stations (4, 5, 6).  3. Machine according to any one of claims 1 and 2, characterized in that the drive wheels (9, 10, 11) of the chain (8) are located in the immediate vicinity of the printing stations (4, 5 , 6) and in that they are all positively controlled from the same drive member (22), some of the intermediate wheels being mounted idly on shafts provided with tensioners (16).  4. Machine according to claim 3, characterized in that the gripping devices (28) associated with the chaste (8) are arranged so as to allow the rotation of the object (2) which they maintain.  5. Machine according to claim 4, of the kind intended for printing bottles with a neck, characterized in that the gripping devices (28) are produced in the form of pliers having the configuration of a pair of scissors whose branches (29, 30) cooperate with means (38, 38 ') of operating them.  6. Machine according to claim 5, characterized in that the two branches (29, 30) of each gripping device (28) are thin and inclined so as to be introduced into the thread of the neck (2a) and to take support against its nucleus.  7. Machine according to claim 5, characterized in that one of the branches (29) of each gripping device (28) is thin and inclined so as to be introduced into the thread of the neck (2a) and to bear against its core, while the other branch (30) has the shape of a dihedral (36) against the internal faces of which the outside of the thread comes to bear.  8. Machine according to claim 5, characterized in that the jaws or ends (29b, 30b) of the branches (29, 30) are interchangeable.  9. Machine according to any one of claims 1 and 2, characterized in that the articulation axes of the chain (8) are hollow and constitute bearings for the pivots (31, 32) of the branches of the gripping devices ( 28).  10. Machine according to claim 5, characterized in that the loading of the bottles (2) on the gripping devices (28) of the chain (8) is carried out by means of a conveyor belt (17) perpendicular to one of its strands and at the front of which the bottles (2) are stopped against a stop (37) while the first bottle of the queue is raised by a plate (40) in order to be gripped by a gripping device (28 ).