GB2056681A

GB2056681A - Pallet testing and sorting machine

Info

Publication number: GB2056681A
Application number: GB8025518A
Authority: GB
Original assignee: Steeg & Hoffmeyer Automation
Current assignee: Steeg & Hoffmeyer Automation
Priority date: 1979-08-23
Filing date: 1980-08-05
Publication date: 1981-03-18
Also published as: FR2463912A3; DE7923956U1; FR2463912B3; GB2056681B

Abstract

A pallet testing and sorting machine characterised by a gripper mechanism (3) which by means of clamping or gripper jaws (4) is adapted to lift and convey the top pallet (1) from a stack (2) thereof for testing, a test mechanism to which the pallets (1) are adapted to be fed individually by the gripper mechanism (3) and which comprises sensing strips (10, 11) adapted to be moved laterally against the pallet (1) for testing the length and breadth dimensions, and a plurality of pressers (13, 14) which act on the loading surface to test the height dimension by subjecting a number of points to loading, an ejection mechanism (16) for rejecting a pallet (1) found to be defective by the test mechanism (7), and a stacking mechanism (18) for the pallets (1) found to be non-defective by the test mechanism (7), said stacking mechanism being adapted to push each pallet beneath the raised stack (19). <IMAGE>

Description

SPECIFICATION Pallet testing and sorting machine In bottling plant and factories, e.g. glass works, pallets are frequently fed mechanically from magasines to loading stations where they are automatically loaded and then carried off mechanically. To obviate jamming and loading errors in such cases, tke pallets must be non-defective, true to size, and of identical types.

Visual inspection is generally all that is carried out to test the pallets and defects are frequently overlooked through lack of care or because they are concealed and occur only under loading. It is also very difficult to assess whether all the important parts are true to size. Attempts have already been made to test pallets by passing them through sensing rollers, but these determine only certain dimensions and defects which occur only under loading remain concealed. The same applies ifjust individual boards or parts ofthe pallet are missing.

The object of the invention, therefore, is to provide a pallet testing and sorting machine which reliably and automatically can eliminate defective pallets.

The solution to this problem is characterised by a gripping mechanism which by means of clamping or gripper jaws is adapted to lift and convey the top pallet from a stack thereof for testing, a test mechanism to which the pallets are adapted to be fed individually by the gripper mechanism and which comprises sensing strips adapted to be moved laterally against the pallet for testing the length and breadth dimensions, and a plurality of pressers which act on the loading surface to test the height dimension by subjecting a number of points to loading, an ejection mechanism for separating a pallet found to be defective by the test mechanism, and a stacking mechanism for the pallets found to be non-defective by the test mechanism, said stacking mechanism being adapted to push each pallet beneath the raised stack.

Accordingly, not only the length and breadth, but also the height, are tested for each individual pallet fed automatically through the machine, and this test is carried out with loading at a number of points. The machine detects any missing, weakened or broken boards or plastic parts on the loading surface or the base of the pallet. A pallet of a different type from the type under test is also detected, even if the dimensions are identical, because the arrangement of boards is different and because of the different loadability.

In a development of the invention, for the purpose of conveying the pallets to the test mechanism the gripping mechanism is vertically movable in a lift frame and the clamping or gripper jaws are horizontally movable. Since the gripper mechanism always takes the top pallet of a stack supplied by a fork-lift truck or automatically, very defective pallets or pallets of very different dimensions cannot lead to a jam because they are not conveyed by the gripper mechanism. Additional test means may also be fitted to the gripper mechanism for this purpose.

In another development of the invention, the test mechanism comprises three serially disposed pairs of pressers each directed in opposition and acting on the base and loading surface of the pallet respective lyforthe purposes of testing the pallet in the middle and the two edge zones. In that case, loadability testing together with testing of the height are carried out at the most important points of the pallet.

Advantageousiy, the test mechanism comprises a conveyor system adapted to convey the pallet in a number of steps, preferably five, each by a fraction of the pallet dimensions transversely of the row of pairs of pressers to a plurality of stations, preferably five, in ordertotestthe height and loadabiíity. A total of 15 pressure measurement points is thus detected so that there is very little likelihood of defects remaining undiscovered.

According to a development of the invention, the ejection mechanism comprises a pusher adapted to push out a defective pallet transversely of the direction of movement of the conveyor system. If desired, the test mechanism may be provided with other measuring and loading means to check additional properties of the pallets. The invention will now be explained with reference to an exemplified embodiment. In the drawings: Figure 1 is a side elevation of a machine as an exemplified embodiment of the invention.

Figure 2 is a plan view of the machine shown in Figure 1.

The pallets 1 for testing are fed to the machine in the form of a stack 2, e.g. by means of a fork-lift truck, individually or in groups manually, or mechanically by means of a conveyor. A gripper mechanism 3 with clamping or gripper jaws 4 is horizontally slidable in guide rails 5 mounted to be vertically movable in a lift frame 6.

The drives for the various parts of the machine and the various directions of movement, and the control system for the sequence of movements, are not shown, nor are they explained, since they are within the knowledge of the average person versed in the art. For example, electric motors and/or hydraulic or pneumatic drives of known type may be used.

The mechanism 3 is lowered and the pallets are engaged by the jaws 4, are lifted, and then conveyed to the left (with reference to Figure 1) as far as the end of the guide rails 5. For lowering purposes, either the rails 5 or else the gripper mechanism 3 on its own is lowered. Pallets not engaged by the gripper mechanism because of different dimensions or considerable defects will accordingly not result in any jamming. They remain on the stack 2 and have to be removed manually.

After being lowered, the pallet passes on to a table 8 of the test mechanism 7. A diagrammatically illustrated conveyor chain 9 with a pusher strip 10 presses the pallet 1 against a stop 11 which is adapted to pivot away. The distance between the strip 10 and the stop 11 can be measured in known manner by non-physical sensing means to show whether the transverse dimension of the pallet 1 is within the specified tolerances. Another pusher 12 (Figure 2) then checks the other transverse dimension of the pallet 1 for tolerances.

If no errors are detected, the pallet 1 is taken between three pairs of pressers 13 and 14 in five conveying steps. On each stop, the two pressers press the pallet in the middle and the two edge zones with a preselected force, the distance between the two pressers and hence the height ofthe pallet being measured. Weak points, broken or missing boards, loose or missing nails are reliably detected with this loading test system.

The pallet then passes on to another table 15 which has just one diagrammatically illustrated transverse pusher 16. If the previous tests have detected defects, the pallet 1 is separated laterally (in the downward direction in Figure 2) by means of the pusher. The program control niay be such that in the event of a defect in the transverse dimensions the pallet is advanced to the table 15, without being tested by the pressers 13, 14and is then pushed out A non-defective pallet passes on to the stacking mechanism 17, which has arms 18 for lifting the stack 19 of non-defective pallets already formed. The pallet which- has just been tested isthen conveyed beneath the lifted stack 19 and thus forms the bottom pallet of the stack 19 for the next cycle.

In orderto avoid manual labour, pallets 1 which are found to be defective can be stacked mechanical lyusinga grippersystem similartothegripper mechanism 3 to deposit the defective pallets successively on to a stack. The transverse pusher 16 may be dispensed with if the gripper mechanism takes the defective pallets direct from the table 15.

Claims

ClAIMS

1. A pallet testing and sorting machine characterises by a gripper mechanism which by means of clamping or gripper jaws is adapted to liftand convey the top pallet from a stack thereoffortesting, a test mechanism to which the pallets are adapted to be fed individually by the gripper mechanism and which comprises sensing strips adapted to be moved laterally againstthe pallet for testing the length and breadth dimensions, and a plurality of pressures which act on the loading surface to test the height dimension by subjecting a number of points to loading, an ejection mechanism for separating a pallet found to be defective by the test mechanism, and a stacking mechanism for the pallet found to be non-defective by the test mechanism, said stacking mechanism being adapted to push each pallet beneath the raised stack.

2. The pallet testing and sorting machine according to claim 1, characterised in thatforthe purpose of conveying the pallets to the test mechanism the gripper mechanism is vertically movable in a lift frame and the clamping or gripper jaws are horizontally movable.

3. The pallet testing and sorting machine accord ing to claim 1 or claim 2, characterised in that the test mechanism comprises three serially disposed pair of pressers each directed in opposition and acting on the base and loading surface of the pallet respectively forthe purposes of testing the pallet in the middle and thetwo edgezones.

4. The pallet testing and sorting machine according to claim 3 characterised in that the test mechanism comprises a conveyor system adapted to convey the pallet in a number of steps, preferably five , each by a fraction of the pallet dimensions transversely of the row of pairs of pressers to a plurality of stations, preferably five, in order to test the height and loadability.

5. The pallet testing and sorting machine accord ing to any one of claims 1 to 4, characterised in that the ejection mechanism comprises a pusher adapted to push out a defective pallet transversely of the direction of movement of the conveyor system.

6. The pallet testing and sorting machine according to any one of claims 1 to 5, characterised in that the ejection mechanism comprises a gripper mechanism adapted to deposit defective pallets on a stack.

7. A pallettesting and sorging machine constructed and arranged substantially as hereinbefore described and as shown in the figures of the accompanying drawing.