Patent Application
20080185768
The present application claims priority to German application no. 10 2007 007 811.2, filed Feb. 16, 2007, which is hereby incorporated by reference in its entirety.
The invention relates to a device and a method for aligning several flat objects, each of which extends in an object plane, and which together form a stack. The objects are, for example, letters or other flat postal items that after alignment are to be processed by a sorting system.
US 2005/0082475 A1 discloses an alignment device, wherein flat object such as sheets of paper are transported on a belt conveyor. For this purpose, the objects are placed vertically on the belt conveyor. Two boundary elements vibrate vertical to the direction of transport of the objects and vertical to the plane of the flat objects and thus align the objects that are located between them. A rotating shaft is rigidly connected to several cams. Each boundary element is rigidly connected to a cam follower that lies against a cam. Thus, rotation of the shaft causes the boundary elements to rotate backwards and forwards. The objects are separated into part stacks. A part stack is transported to a boundary wall and is there aligned by means of further boundary elements that align it with one edge against the boundary wall.
An aligning device described in US 2001/022261 A1 is, for example, used to align pieces of wood. The device described therein includes a belt conveyor and an adjacent U-shaped aligning device. The aligning device has two vertical side pieces and a saw-tooth, jagged horizontal base. The aligning device slopes in the direction of the conveying device and vibrates vertical to the direction of conveyance. The objects are thus aligned.
A device is described in US 2003/0062670 that aligns rectangular sheets of paper at two edges. The sheets of paper are fed in succession to a supporting device, which has a base and two boundary walls. The corner at which the base and both walls meet is the lowest point of the supporting device and the base slopes to this corner. A motor sets the supporting device in vibration so that each paper sheet slides to a position in which two edges of the sheet lie against both walls.
A letter input station with a vibrator is known from EP 1676796 A1. A stack of flat postal items stands vertically on a belt conveyor and is fed by the belt conveyor to a separating device. The conveying device is vertical to those parallel planes in which the flat postal items extend. The postal items lie on a flat plate. A vibrator vibrates the belt conveyor while the belt conveyor conveys the stack.
The objects to be aligned are, e.g., letters that are to be processed by a sorting system. The feeder of this sorting system has to reliably separate the letters and transport them in succession through the system for further processing. So that it can reliably perform this task, the letters must be aligned before separation and in fact on two edges that stand vertical to each other. This aligning should be carried out quickly and even when objects with different dimensions are to be aligned.
The object of the invention is to provide an aligning device, and an aligning method that quickly align a stack of flat parallel objects on two edges even if the objects have different dimensions.
Accordingly, the inventive device is capable of aligning several flat objects. These objects each extend in one object plane and together form a stack. The device includes a supporting device for supporting the objects, two boundary elements, a drive for the backwards and forwards movements of the boundary elements, and a motor. The supporting device has two flat aligning surfaces for aligning the objects. Both these aligning surfaces lie in two planes that abut each other at a straight edge. Both aligning surfaces slope towards the edge. The motor is designed so that it is capable of vibrating the two aligning surfaces.
The at least two boundary elements can be swung into an engaging position. In this engaging position, the at least two boundary elements hold the stack with the objects when the stack is located on the supporting device and between the boundary elements. The drive is connected to the boundary elements in such a way that it can move the boundary elements backwards and forwards parallel to the edge when they are in the engaging position.
The inventive device effects an alignment in two different ways. The force of gravity forces the objects to slide downwards along both downwards sloping aligning surfaces and thus become aligned at two edges. And, in the engaging position, the boundary elements vibrate the flat objects that stand vertically on the edge between the aligning surfaces, backwards and forwards, i.e., in two directions. These varied movements cause a fast alignment.
The objects are vibrated backwards and forwards particularly well if at least three, preferably five, boundary elements are provided. These divide the stack of flat objects into at least two, preferably four, part stacks and vibrate these part stacks independently of each other.
The boundary elements preferably sit on a holding device, e.g., a shaft. In one arrangement, the drive moves the holding device backwards and forwards and the boundary elements are thus moved backwards and forwards. In a different embodiment, the boundary elements are moveably arranged on the holding device in such a way that they can be moved backwards and forwards parallel to the edge. The drive is connected via a transmission device, e.g. a cable or chain, to the boundary elements.
The novel features and method steps characteristic of the invention are set out in the claims below. The invention itself, however, as well as other features and advantages thereof, are best understood by reference to the detailed description, which follows, when read in conjunction with the accompanying drawings, wherein:
In the exemplary embodiment, the device is used to align a stack of letters and/or other flat rectangular postal items at two edges K1, K2. These postal items function as the objects to be aligned. Further processing of the postal items Se1, Se2 requires that they have been aligned at both edges K1, K2.
In the exemplary embodiment, the aligning device includes a vibrating table. This vibrating table has two aligning surfaces 1, 2 that abut each other at an edge K and are rigidly connected to each other. The aligning surfaces 1, 2 extend flat in two planes. Both aligning surfaces 1, 2 slope steeply towards the edge K and stand vertically on each other. In the exemplary embodiment, the postal items Se1, Se2 to be aligned have two edges K1, K2 that are also vertical relative to each other.
The direction of view in
The aligning surfaces 1, 2 are made from a smooth, hard-wearing material, such as metal or hard plastic. The vibrating table has a frame with four legs 4.1, 4.2, 4.3, 4.4 which provides it with a stable mounting. A motor 3 is connected to the frame and is designed to set both aligning surfaces 1, 2 in vibration. The motor 3 is firmly connected to the frame and is located under the aligning surfaces 1, 2. It can be switched on and off. The motor vibrates both the aligning surfaces 1, 2, for example in a manner described in US 2003/0062670 or EP 1676796.
Each of the postal items extends in an object plane that is vertical to the drawing plane of
In the exemplary embodiment, the aligning device has at least three boundary elements 5.1, 5.2, etc. that are attached to a holding device 6 in such a way that they can be swiveled independently of each other relative to the holding device 6. The holding device 6 is connected to the frame and therefore stands on the four legs 4.1, 4.2, 4.3, 4.4. Each boundary element 5.1, 5.2 etc., can be swiveled backwards and forwards between a position in which it engages in the stack of postal items Se1, Se2 that lies on both aligning surfaces and in a position in which the stack can be moved past on the boundary element.
In
Two boundary elements form the outer boundary elements. In the example in
In the arrangement shown in the illustrations the device has five boundary elements 5.1,-5.5 etc. This has proved to be a more satisfactory compromise between the requirements for a fast alignment of the postal items and a simple arrangement of the device. The postal items Se1, Se2 are vibrated through in two different ways. On one hand by means of the vibrations which are imparted to the supporting surfaces 1, 2 and transmitted to the postal items Se1, Se2, and, on the other hand, by the backwards and forwards movements of the boundary elements 5.1, 5.2 etc. that cause the postal items Se1, Se2 to tilt backwards and forwards.
Preferably, the boundary elements 5.1, 5.2 etc. are connected to the holding device 6 in such a way that each boundary element can be swiveled into the engaging position independently of the other boundary elements. At the same time, all the boundary elements 5.1, 5.2 etc. are connected to each other in such a way that a movement of a boundary element from the engaging position carries the other boundary elements with it, i.e. causes each of the other boundary elements to be swiveled into the non-engaging position.
Preferably, the holding device 6 is designed as a shaft that runs parallel to the edge K between the planes of the aligning surfaces 1, 2. Each boundary element 5.1, 5.2 etc. is attached to this shaft in such a way that it can be rotated backwards and forwards between the two positions. Each boundary element can be rotated to the engaging position independently of the other boundary elements.
In another embodiment, the boundary elements are connected to the holding device 6 in such a way that they can be pushed backwards and forwards between both positions, preferably in a linear movement. Mixed forms are also possible where each boundary element 5.1, 5.2 etc. can be moved backwards and forwards between both positions by a superpositioning of a rotating and linear movement.
An operator places the stack of postal items Se1, Se2 to be aligned on the aligning surfaces 1, 2 and first moves one of the two outer boundary elements 5.1 or 5.5 to a position in which this outer boundary element forms the boundary of the stack, viewed in the direction of the edge K. The stack is thus held by the first swiveled boundary element. In the example in
The operator then moves at least one further boundary element 5.2, 5.3, 5.4 to a position in which it engages in the stack and divides the stack into two part stacks. The further boundary element 5.2, 5.3, 5.4 is then also in the engaging position. Postal items Se1, Se2 lie loosely between the boundary elements 5.1, 5.2 etc. in such a way that they can tilt to a certain extent and are thus not tightly held.
The device has a drive 9.1, 9.2 designed to move the boundary elements backwards and forwards relative to the holding device, i.e., in two opposite directions parallel to the edge K between the aligning surfaces 1, 2. A transmission device 8 transmits movements from the drive 9.1, 9.2 to the boundary elements 5.1, 5.2 etc. If the holding device 6 is designed as a shaft, the drive 9.1, 9.2 moves the boundary elements 5.1, 5.2 etc. backwards and forwards parallel to the shaft.
In the example in
Preferably, the transmission device 8 is designed so that the distance between at least two adjacent guide elements varies during the backwards and forwards movement. This has the effect of varying the slope angles of the postal packages Se1, Se2 relative to the vertical, thus further accelerating the aligning.
The transmission device 8 for example includes a cable or a chain or other flexible oblong transmission element. This transmission element 8 connects all the boundary elements to each other and to the drive. The transmission element 8 then tightens when the drive 9.1, 9.2 moves the boundary elements 5.1, 5.2 etc. in one direction, which leads to an increased distance between the boundary elements 5.1, 5.2 etc. The inertia of the masses of the postal items and the boundary elements 5.1, 5.2 etc. causes the distance to be reduced.
The arrangement with at least three boundary elements means that the backwards and forwards movement is transmitted to the at least two part-stacks that occur and the aligning is carried out even faster.
After the stack is positioned between the outer boundary elements 5.1, 5.5 and at least one further boundary element 5.2, 5.3, 5.4 engages in the stack, the alignment of the postal items begins. On the one hand, the motor 3 sets both aligning surfaces 1, 2 in vibration, after the operator has switched it on. On the other hand, the drive 9.1, 9.2 moves the boundary elements 5.1, 5.2 etc. backwards and forwards parallel to the edge. The backwards and forwards movement means that the postal items during the movement have different slope angles with respect to the vertical. In conjunction with the vibration, this further reduces the friction between the postal items and the force of gravity then aligns the postal items faster against the aligning surfaces 1, 2.
If the backwards and forwards movement of the boundary elements 5.1, 5.2 etc. has a sufficiently large amplitude, the postal items Se1, Se2 are even tilted backwards and forwards so that they pass through a vertical position during tilting, i.e. are inclined to one side and then to the other. Preferably, the frequency with which the drive 9.1, 9.2 moves the boundary elements backwards and forwards can be varied. In this way the frequency can be matched to different postal items and environmental conditions, e.g., different ambient humidity, temperature, or different average dimensions of the postal items. After a preset time barrier is reached, the operator switches off the motor 3 which generates the vibration, as well as the drive 9.1, 9.2 for the boundary elements. Then, the operator, or a further drive, swivels the boundary elements 5.1, 5.2 etc. to the non-engaging position. In the case of rotatably mounted boundary elements, the operator rotates a boundary element, preferably an outer boundary element 5.1, 5.5, to a non-engaging position. This causes all the other boundary elements to also be turned off.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2007 007 811.2 | Feb 2007 | DE | national |
