Patent Application
20050126884
The invention relates to an apparatus for selective diversion of objects such as containers, packing, packing units of different mass. The apparatus has a first transport device for the objects and a diversion device for diverting predetermined objects from the first transport device onto a second transport device. The intensity with which the objects are diverted from the first transport device onto the second transport device is controlled by means of a control device.
Such diversion apparatuses are used to divert faulty objects, e.g. containers which are not completely full, from a flow of such objects.
From WO 00/68120 (=DE-U-299 08 036) it is known to control the intensity with which objects are diverted in such a way that the objects receive a diversion impulse of differing strength transversely to their direction of transport and thus reach one of several second transport devices running parallel alongside each other.
A similar apparatus is known from DE-A-100 07 627 in which upright bottles are diverted by means of a single impulse of a pusher, while horizontal bottles are diverted by means of an impulse sequence of the pusher.
An apparatus for sorting out faulty packaging units is known from DE-C2-36 23 327, the angle at which the pusher pushes the packaging units from the conveyor belt being automatically controlled. The angle is set depending on the transport speed of the conveyor belt and the vector perpendicular to it of the required pushing speed.
An apparatus for sorting out faulty packaging units, in particular bottles, is known from DE-C1-37 34 599, the pusher being driven by a cam and developed as a slide plate to which a brushing segment is attached. The acceleration and the speed of the slide during the sorting-out process are determined by the shape and the speed of rotation of the cam. It is to be thereby achieved that the path by which the packaging units to be sorted out are pushed is independent of the degree of filling of the packaging units.
Diversion devices have a diversion element, displaceable transversely to the direction of transport, which is driven pneumatically or by electric motor. The diversion element can also be in an air jet which pushes an object to be diverted transversely to the direction of transport. In the case of diversion apparatuses in which objects of different mass are to be diverted onto a second transport device, there is the difficulty that light objects are more markedly accelerated by the diversion device and thereby obtain a higher speed component transversely to the direction of transport than heavier objects.
The object of the invention is to create a diversion apparatus which imparts a transverse impulse to objects regardless of their mass and which leads to a roughly equally wide displacement of the objects transversely to the direction of transport.
This object is achieved according to the invention by a device for establishing the progress of the diversion of an object, the control device activating the diversion device more strongly or for longer depending on the established progress if the progress is less, or vice versa.
Due to their greater mass heavy objects initially have a smaller speed component transversely to the direction of transport from the diversion element. The progress of the diversion is monitored by means of a sensor for example by measuring the period of time that the diversion element or the object to be diverted requires in order to reach a certain point of its diversion movement. When the sensor reports that this period of time is over a certain value the diversion device is activated more strongly for the remainder of the diversion movement, i.e. in the case of a pneumatic diversion device the diversion element is extended with a higher pressure or further and in the case of a diversion element driven by electric motor the voltage of the electromotor drive is increased or applied for a longer period. In the case of a diversion element in the form of an air jet, the nozzle pressure is increased or likewise applied for a longer period.
In another embodiment the speed reached by the diversion element at a certain point in time after the start of the diversion process is measured. An angle transmitter, a linear encoder, a speedometer or an acceleration indicator can be used for this. The basic idea is in each case that a heavier object requires more time for the predetermined section or has reached a lesser speed than a lighter object, so that the diversion device has to be activated correspondingly more strongly or for longer.
The diversion device can also be controlled by integrating in the diversion element a force sensor which measures the force with which the diversion element presses against the object. An object of greater mass will offer greater resistance to the diversion element, so that a higher force is measured.
In the case of a diversion element driven by electric motor the power consumption can also be used as a criterion.
Depending on the established progress the diversion device is activated, the activation being greater or for longer for a lesser progress and vice versa. Thus if a relatively low speed or a long extension time is ascertained at a predetermined point, the diversion device is activated more strongly or for longer. In the case of a pneumatic drive of the diversion device e.g. the pressure supplied to the cylinder is increased or the diversion element is further extended, i.e. the object is accelerated for a longer period by the diversion element transversely to the direction of transport. Correspondingly in the case of a drive by electric motor the supplied power is increased or the diversion process is prolonged.
The diversion apparatus according to the invention can also be used to divert objects of different mass from a first transport device onto one of several second transport devices. The further away from the first transport device the concerned second transport device is, the more strongly must the diversion device be activated, the activation additionally taking place according to the invention corresponding to the mass of the object.
The diversion apparatus according to the invention is suitable in particular for transport units in which the objects are transported past the diversion element at a very small distance of at most a few millimetres. The distance is to be particularly small compared to the length of the diversion movement of the diversion element. If the distance is greater, e.g. 2 cm, the diversion apparatus according to the invention can also be used for stable objects, such as beer crates or mineral-water crates if the distance is at least always the same.
An embodiment of the invention is explained below with reference to the drawing. There are shown in:
A diversion device 10 is arranged next to a first conveyor 11 which is a link chain conveyor. The first conveyor 11 conveys an object 14, which is a beer crate in the represented example, past the diversion device 10. The diversion device 10 serves to push certain objects 14, e.g. not completely filled beer crates, from the first conveyor 11 onto a second conveyor 12 running parallel alongside it and thus exclude them from the further production process.
The diversion device 10 contains a diversion element 16, which can be swivelled by means of a swivel arm 18. The diversion element 16 is a plate aligned in the direction of transport, and the swivel arm 18 is designed so that the alignment of the diversion element 16 is maintained upon swivelling out. To this end the swivel arm 18 consists of a main lever 19 and a parallel lever 20.
The pivot points 21 of the main lever 19 and of the parallel lever 20 are arranged vis-à-vis the diversion element 16 at a distance in the direction of transport indicated by the arrow 22, so that, upon swivelling out, the diversion element 16 moves at the same time roughly in the direction of transport. The object 14 is thus pushed essentially transversely, upon swivelling out of the diversion element 16, on the first conveyor 11, without a greater relative movement in the direction of transport taking place between the object 14 and the diversion element 16.
The main lever 19 is roughly T-shaped and is coupled at the bottom end of the vertical T-column in the pivot points 21. In the starting position shown in
The period of time t which passes between the triggering of the swivel cylinder 28 and the occurrence of the trigger signal serves as a measure of the mass of the object 14. The longer this period of time t, the greater the mass of the object 14. The length of the trigger time T of the swivel cylinder 28 is controlled according to this period of time t by means of a control device 32. There are three gates lying one behind the other for the period of time t. If the period of time t falls within the range of the first gate G1, trigger time T1 is chosen. If the period of time t falls within the range of the second gate G2, trigger time T2 which is greater than T1, is used. If the period of time t falls within the third gate G3, then trigger time T3 which is greater than T2, is chosen (
The trigger times T are established experimentally and taught to the control device 32. In the represented embodiment the trigger time T is controlled stepwise. However, it is preferably controlled continuously via a characteristic line. For this, several points of the characteristic line are established experimentally and the curve sections lying in between are interpolated.
When experimentally establishing the trigger times T or the characteristic line, the influence of the differing friction of heaver and lighter objects can be taken into account.
List of Reference Numbers
| Number | Date | Country | Kind |
|---|---|---|---|
| 201 15 478.1 | Sep 2001 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP02/09982 | 9/6/2002 | WO |
