Transport device in a packaging machine

Details Transport device in a packaging machine Transport device in a packaging machine

1999-07-15

2001-12-25

Bidwell, James R. (Department: 3651)

Conveyors: power-driven

Conveyor system for arranging or rearranging stream of items

By laterally or vertically moving successive items in...

Reexamination Certificate

active

06332528

ABSTRACT:

This application claims Paris Convention priority of DE 198 39 391.1 filed Aug. 28, 1998 the complete disclosure of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
The invention concerns a transport device in a packaging machine for transporting a plurality of packages and/or products together which are disposed next to each other transverse to the transport direction, wherein a guiding device is provided for changing the mutual separation of the packages and/or products transverse to the transport direction.
In filling and packaging machines, the products and/or the packages pass through various processing stations and are transported between same by means of transport devices e.g. in the form of conveyor belts. In the event that a plurality of products and/or packages are to be transported together i.e. in a group aligned next to each other, the products frequently fail to have the desired sideward separation. When, for example, three tubes are to simultaneously filled and then further transported to the packaging unit, they gain entrance to the conveyor belt with a mutual sideward separation of approximately 50 mm. Since however a larger mutual sideward separation of approximately 75 mm is desired for transfer to the downstream processing station, they must be displaced sidewardly relative to each other during transport.
Towards this end, conventional installations utilize guiding fins disposed in a stationary fashion above the conveyor belt which direct the sidewardly disposed tubes in an outward direction to increase the mutual separation between the tubes transverse to the transport direction. It has however turned out that the sideward tubes are slowed substantially during the deflecting motion by the guiding walls along which they slide so that they trail the central unretarded tube by a significant amount. Since however the tubes must be simultaneously introduced at the end of the conveyor belt into the subsequent processing station, the leading middle tube must wait at the end of the conveyor belt for the trailing sideward tubes. This increases the processing time. Moreover, a special device must be provided for accepting the sequentially arriving tubes and to simultaneously feed same into the processing station (in particular, a cartoning station), as a result of which the structural complexity is increased.
It is the underlying purpose of the invention to create a transport device in a packaging machine of the above mentioned kind with which the mutual sideward separation between the products and/or packages can be changed without having them precede or trail each other.
SUMMARY OF THE INVENTION
This purpose is achieved in accordance with the invention with a transport machine in that the guiding device comprises a plurality of conveyor belts travelling next to each other in the transport direction, each for the acceptance of one package and/or a product, which are disposed at an angle with respect to each other in such a fashion that their mutual separation transverse to the transport direction changes in the transport direction, with the conveyor belts being substantially of equal length and capable of being driven by a common drive device.
In accordance with the invention, the mutual separation between individual tubes or products of a group is not increased or changed by sideward displacement forces on the conveyor belt. Rather, the device comprises, at least in sections, a plurality of conveyor belts corresponding to the number of products or tubes, which travel diagonally at a slight angle with respect to each other. When a tube is dispensed at the input side of each conveyor belt, the mutual sideward separation of the tubes changes as they travel along these individual conveyor belts. At the end of the conveyor belts, the tubes can either be directly passed to the downstream processing station or an additional single common conveyor belt is provided for all tubes.
The slight diagonal disposition of the conveyor belts relative to each other leads to a slight difference in the transport path length traveled by the individual tubes. In order to guarantee that the tubes arrive simultaneously at the end of the conveyor belt, a controller can be provided for driving the belts with differing speeds to thereby compensate for deviations. These deviations are, however, generally so small that compensation can be taken when dispensing the tubes on the conveyor belts or when removing them therefrom. This facilitates, in a preferred embodiment of the invention, that the conveyor belts are substantially of equal length and are driven by a common drive device to minimize the structural difficulty and expense and moreover to guarantee that the conveyor belts move with equal speeds.
The conveyor belts are conventionally guided, at least in their end regions, by means of rollers. A preferred embodiment of the invention provides that the conveyor belts have a common drive shaft on which a plurality of rollers are borne. Each roller guides and thereby drives one conveyor belt. In many cases, three conveyor belts are disposed next to each other, wherein the central conveyor belt travels straight in the transport direction and the two outer conveyor belts are each slightly slanted towards the outside. The invention however is applicable for all transporting devices having at least two conveyor belts. Since the axes of rotation of the individual conveyor belt rollers on the ends do not coincide with each other, means must be provided for equal driving of all conveyor belts using a common drive shaft. This is achieved in accordance with the invention in that one of the rollers, preferentially a middle roller i.e. the roller associated with the middle straight conveyor belt, is mounted for mutual rotation with the drive shaft, wherein the drive shaft extends substantially at right angles to the longitudinal path of the conveyor belt and thereby to the transport direction. The sideward rollers, each guiding one of the diagonally extending conveyor belts, do not receive their rotational motion directly from the drive shaft, rather are indirectly connected thereto for rotational drive. Towards this end, the sideward rollers are borne for free rotation on the drive shaft and can freely exercise a reciprocal motion thereon, i.e. a pivot motion about a pivot axis extending perpendicular to the drive shaft. A rotational motion of the sideward rollers which is synchronized with the rotational motion of the drive shaft and thereby of the middle roller, is effected by connecting each sideward roller to the middle roller using a transfer element. The transfer element is thereby configured to secure rotational coupling between the middle roller and each side roller while nevertheless allowing the reciprocal motion of the sideward rollers relative to the middle roller and thereby relative to the drive shaft. In a particularly simple embodiment, the transfer element is a helical spring surrounding the drive shaft. The rotational motion of the middle roller is transformed by the rotation of the helical spring about its longitudinal axis substantially without elastic deformation, whereas the reciprocal motion of the side rollers is facilitated by the elasticity of the helical spring in its longitudinal direction. Alternatively, a bellows can also be utilized as a transfer element.
Further details and features of the invention can be extracted from the following description of an embodiment with reference to the accompanying drawing.


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