GB2033331A

GB2033331A - Tray unloading and unstacking apparatus

Info

Publication number: GB2033331A
Application number: GB7933760A
Authority: GB
Original assignee: Staalkat BV
Current assignee: Staalkat BV
Priority date: 1978-10-04
Filing date: 1979-09-28
Publication date: 1980-05-21
Also published as: GB2033331B; NL183288B; NL183288C; NL7810040A; DE2938688A1

Abstract

Apparatus for unloading and unstacking a plurality of trays (4) filled with articles, such as eggs or tomatoes, and supplied by means of a conveyor (1), comprises a lifting table (6) mounted on a shaft (20) that is both rotatable and movable upwardly and downwardly, means (36, 37) for gripping and unloading the articles and means (41-43) for gripping and unstacking the trays. A pushing plate (5) is provided for sliding a stack from the supply conveyor (1) to the lifting table (6), and the means for gripping and unloading the articles and the means for gripping and stacking the trays are arranged on opposite sides of the lifting table. Preferably, a plurality of lifting tables (6) are arranged laterally of the supply conveyor and are controlled by a photo-electric sensor so that successive uppermost trays of the stacks are moved upwardly to the same positions relative to the article unloading and tray unstacking means. <IMAGE>

Description

SPECIFICATION Unstacking Apparatus This invention relates to an apparatus for unstacking a plurality of trays filled with articles, such as eggs, tomatoes and the like, and supplied by means of a conveyor, said apparatus comprising a lifting table mounted on a shaft that is both rotatable and movable up and down, and means for gripping the trays.

It is an object of the present invention to improve an apparatus of this kind, as disclosed in Dutch patent 142,91 6, in such a manner that not only are the filled trays of stack separated from each other, but in addition the article and the tray are separated from each other. Another object of the invention is to provide an apparatus which, in addition to a high processing capacity, is quiet in operation.

According to the invention, the apparatus is characterized in that means are provided for sliding the stack from the supply conveyor onto the carrying platform of the lifting table, and that there are arranged on opposite sides of the lifting table means for gripping the articles and said means for gripping the trays.

In this arrangement, in order to increase the capacity still further, a plurality of carrying platforms may be arranged laterally of the supply conveyor. By removing the stacks out of the path of the supply conveyor, the supply of fresh stacks during the unstacking can continue, as a consequence of which these can be moved at a low velocity in spite of the desired high capacity.

In one embodiment of the invention, the means for gripping the articles consist of a suction box suspended from two rotatable carrying arms, said box having suction cups, and the means for gripping the trays consist of gripping elements suspended from two rotatable carrying arms, the carrying arms for gripping the trays being disposed outwardly of the carrying arms for gripping the articles.

It is thus achieved that, immediately after picking-up of the articles and the beginning of their removal, the removal of the trays can begin, too, so that a further increase in processing capacity is obtained.

In order that the uppermost, filled tray of a stack may be adjusted to the correct position relative to the means for gripping the articles or the tray, the up-and-down movement of the shaft with the lifting table may be effected by means of a cam disc, driven by a motor actuated by a photoelectric cell provided adjacent said means for gripping the articles and the trays. It is thus achieved that trays of different heights or filled with articles of different sizes can be processed with the apparatus according to the invention without further ado. This in contrast to the prior apparatus, in which the up-and-down movement of the shaft takes place over a predetermined distance.

One embodiment of the unstacking device according to the invention will now be described, by way of example, with reference to the accompanying drawings, in which Fig. 1 is a diagrammatic front-elevational view of an unstacking apparatus according to the present invention; Fig. 2 shows a plan view of the apparatus shown in Fig. 1, omitting the means for gripping the articles and the trays; and Fig. 3 shows a detail of the apparatus of Fig. 1, with the parts in a different positions.

Referring to the drawings, there is shown an unstacking apparatus comprising a supply conveyor 1 equipped with an endless roller chain 2, driven via a transmission assembly 12 by a motor 13, and mounting tables 3 arranged to receive a stack of filled trays 4. When the foremost stack 4 supplied by conveyor 1 (in the twin-mode shown in the drawings the foremost two stacks) has reached the position shown in Figs. 1 and 2, the stack is pushed by means of a pusher 5 from table 3 over a supporting plate 57 onto a lifting table 6.

Pusher 5 is operated by a linkage 7 constructed so that a stud 8 thereof is capable of performing a horizontal movement. Mounted for rotation on stud 8 is a block 9 fixedly connected to pusher plate 5. Secured to block 9 is further a guide rod 10 extending through a guide block 11 fixedly connected to a frame 58, shown diagrammatically. The linkage is driven by a crank connecting rod mechanism 14, which is driven via sprocket 15, a chain 16 and a sprocket 17 buy a motor 1 8.

Lifting table 6, which is provided with a guide rod 1 9 for receiving the stack in the correct position, is mounted on a shaft 20 journalled in a sleeve 21 fixedly connected to a hub 23 of a sprocket 24, which parts are together enclosed in a frame section. In order to prevent shaft 20 from rotation, the shaft is equipped with a key 20, sleeve 21 having a key-way not shown. Sprocket 24 is driven by means of chain ?5 by a motor ?6 (Fig. 2) for turning the filled trays through 900, in order that each of the trays, which are stacked alternately in one direction and in the other, may be brought below the article and tray removing means in the correct position.

The up-and-down movement of shaft 20 is effected by a lever 27, one end of which is provided with a roller 59 mounted between two discs (not shown) of shaft 20, and the other end of which is pivoted to the frame. Lever 27 is further provided with a cam roller 28 which rests on a cam disc 29 mounted on a shaft 30. Mounted on this shaft is further a sprocket 31, which by means of a chain 32 and a sprocket 33 is driven by a motor 34. Motor 34 is actuated by a photoelectric cell 35 (Figs. 2 and 3) disposed in the vicinity of the means for gripping the trays and the articles. The stack of trays is thereby intermittently moved upwardly in such a manner that the uppermost one is always in the same position relative to the article and tray removing means, irrespective of the height of trays and the size of the articles.When the last tray of each stack has been removed from the lifting table 6 further rotation of cam disc 29 will cause table 6 to be lowered again back into its starting position.

When a new stack of filled trays has been moved onto the lifting table, motor 34 is again switched on by means of a switch, not shown, actuated by plate 5, until the uppermost tray with articles actuates the photo-electric cell, whereafter the cycle described is repeated.

The removal of the articles is effected by means of a suction box 36 equipped with suction cups and suspended from two carrying arms 37 mounted on a shaft 38 equipped with a sprocket 39, which shaft 38 is rotatable so that after the articles have been picked-up by the suction cup they can be supplied to a supply track 40 of a sorter not shown.

The empty trays are removed by means of gripper arms 41 secured to strips 42 which are pivoted to carrying arms 43 arranged outwardly of arms 37 and mounted on a shaft 44 equipped with a sprocket 45 and rotatable between a position for receiving a tray and a position for delivering a tray to a chain conveyor 46.

Sprockets 39 and 45 are driven by means of chains 47 and 48, respectively, by sprockets 49 and 50, respectively. Sprocket 49 is mounted on a shaft 51 actuated by a crank-connecting rod mechanism 52, the other end of which is connected to a shaft 53. This shaft is driven via sprockets and a chain, not shown, by a motor 54.

Operatively associated with said shaft 53 is a second crankconnecting rod mechanism 55, the other end of which is connected to a shaft 56 on which said sprocket 50 is mounted.

By virtue of this construction it is achieved that each time immediately after the removal of articles has begun, the trays can be removed as well, which makes for extremely fast unstacking.

It is noted in this connection that, as shown in Fig. 3, a second sprocket is mounted on each of shafts 38 and 44, which sprockets are connected by means of a chain to a sprocket connected to suction box 36 and strips 42, respectively, in order that these may be maintained in a horizontal position during their movement.

It will be clear that a large number of modifications are possible without departing from the scope of the invention.

Claims

1. Apparatus for unstacking a plurality of trays filled with articles, such as eggs, tomatoes or the like, and supplied by means of a conveyor, said apparatus comprising a lifting table mounted on a shaft that is both rotatable and movable upwardly and downwardly, means for gripping the articles and means for gripping trays, characterized by means, for example a pushing plate, for sliding a stack from the supply conveyor to the carrying platform of the lifting table, and in that there are arranged on opposite sides of the lifting table means for gripping the articles and said means for gripping the trays.

2. Apparatus as claimed in claim 1, wherein a plurality of carrying platforms are arranged laterally of the supply conveyor.

3. Apparatus as claimed in claim 2, wherein the means for gripping the articles comprise a suction box with suction cups and suspended from two rotatable carrying arms, and the means for gripping the trays comprises gripper elements suspended from two rotatable carrying arms, characterized in that the carrying arms for gripping the trays are arranged outwardly of the carrying arms for gripping the articles.

4. Apparatus as claimed in any of claims 1-3, wherein the up-and-down movement of the shaft of the lifting table is effected by means of a cam shaft driven by a motor actuated by a photoelectric cell arranged adjacent to the means for gripping the articles and the trays.