GB2062897A

GB2062897A - Method and apparatus for orientating a flat article

Info

Publication number: GB2062897A
Application number: GB8031192A
Authority: GB
Original assignee: KERAMIK WTB VEB
Current assignee: KERAMIK WTB VEB
Priority date: 1979-11-02
Filing date: 1980-09-26
Publication date: 1981-05-28
Also published as: JPS56100176A; ES8200042A1; IT1146170B; DE3027201A1; IT8049558A0; FR2468565A1; DD146422A1; FR2468565B1; GB2062897B; DE3027201C2; ES495241A0

Abstract

A method of automatically orientating a flat article such as a ceramic plate with a shaped edge comprises positioning the article (1) on a rotatable table (7) and bringing up to the edge of the article (1) a plurality of sensors consisting of associated pairs each comprising a nozzle (9) and a pressure sensor (10). The nozzles (9) direct respective air jets towards their associated pressure sensors (10), which latter produce output signals when they detect a pressure rise due to impingement of the air jet. The air jets are directed across the edge of the article (1) at positions such as to be interrupted by the edge except when the article (1) is in the required orientation in which case the air jets pass across recesses in the edge to reach the associated sensors (10) which then produce an output signal to stop the rotation of the table. <IMAGE>

Description

SPECIFICATION Method and apparatus for orientating flat articles such as ceramic plates The present invention relates to a method and to apparatus for performing the method, for orientating flat articles such as ceramic plates.

The articles, for example ceramic plates, when in their correct orientation can then be decorated by transfer or other printing technique.

The requirement for correct orientation arises particularly in connection with the decoration of flat plates having a shaped edge, that is an edge with recesses or fluting therein.

At present the positioning for transfer printing of ceramic articles, such as flat crockery, especially plates, is effected by hand; there is no known machine for effecting such positioning automatically. However, manual positioning of the ceramic articles has the disadvantage of requiring a large time and consequently only a relative low output from the following colour print transfer machine can be obtained. Other disadvantages of the known manual positioning are the unfavourable working conditions and the imprecise positioning of the plates.

The present invention seeks therefore to avoid these known disadvantages, and to provide a method and apparatus which make it possible automatically to position hard ceramic articles such as plates in a required position for colour print transfer machine. According to one aspect of the present invention this is achieved by a method of orientating a flat article having a shaped edge, such as a ceramic plate, comprising the steps of mounting the article on a rotatable table, positioning one or more pairs of cooperating transmitters and receivers at the edge of the article in positions such that the edge of the article will not obstruct transmission of a signal from a transmitter to its associated receiver when the article is in its correct orientation, and rotating the table until the transmitted signal or all the transmitted signals is or are received at cooperating receivers indicating that the article is correctly orientated, the receivers generating a signal which is used to stop the rotation of the table with the article in this orientation.

According to another aspect the present invention provides apparatus for orientating a flat article having a shaped edge, such as a ceramic plate, comprising a rotatable table for receiving the article, and one or more pairs of cooperating transmitters and receivers positionable at the edge of the article in positions such that the edge of the article will not interrupt transmission from the or each transmitter to its associated receiver when the article is in the correct orientation, and means for stopping rotation of the table when a signal is received from the or each receiver.

The transmitter and receiver may be respectively means for producing an air jet and a pressure sensor.

In a preferred embodiment the working pressure of the transmitters lies between 0.12 and 0.6 MPa, and the working pressure of the receivers lies between 0.03 and 0.16 MPa.

Alternatively the or each transmitter and receiver is a light source and a photoelectric detector respectively.

One embodiment of the invention will now be more particularly described by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view of the device, showing only one half of a plate to be positioned thereby; and Figure 2 is a cross-sectional view taken on the line ll-ll of Fig. 1.

Referring now to the drawings, the automatic positioning device comprises a turntable 1 mounted so as to be turnable about a vertical central axis and driven to rotate by a motor 7. The turntable 1 has an upper surface which can receive a plate 2 and engage the plate with relatively high friction so that the plate is turned with the turntable.

A sensing device comprises an arcuate segment support 4 carrying two air pressure sensors 1 3. These sensors 1 3 each comprise an air jet nozzle 9 for emitting a stream of air under pressure and a receiver nozzle device 10 aligned with the emitter nozzle 9 for receiving the air jet emitted by the nozzle 9.

The nozzle device 10 includes means for generating an electrical signal in response to reception of the air stream from the emitter nozzle 9, and this signal is transferred to an amplifier 11 where it is amplified and used in a manner which will be described in more detail below.

The nozzles of each of the two sensors 1 3 are carried on respective holders 14 which are mounted on the arcuate segment support 4.

This latter is pivoted to a lug carried by a rocker lever 5 mounted by a pivot 1 6 to a fixed frame 1 7. The lever 5 is biased by a tension spring 6 to an operative position, and can be retracted by the action of a linear fluid pressure actuator 3.

A plate 2 to be positioned by the device is mounted on turntable 1 and is then centred by automatic means (not shown). The actuator 3 is then retracted allowing the lever 5 to turn, and the segment 4, which is pivotably secured to the lever 5, is pressed by the action of the biasing spring 6 via the lever 5 against the plate 2 mounted on the table 1.

The drive motor 7 is now turned on and rotates the turntable 1 on which the plate 2 is mounted. The plate 2 is turned until both of the two air jets 8, which are emitted by the nozzle 9, pass unobstructed, through the two recesses on the outer edge of the plate, to the receivers 10. When both pressure signals ar rive at respective receivers 10, these are converted into electrical signals, amplified in the circuit 11, and used to switch off the drive motor 7. The recesses in the outer edge of the plate 2 now have a very specific angle with respect to a fixed vertical reference plane 1 2 passing through the centre of the plate 2. The plate 2 is thus fully positioned and can now be automatically passed on to a colour print transfer machine.

Each of the sensing devices 13, comprising the two nozzles 9 and 10, are fixed to the respective holder 14 which is securely fixed onto segment 4. The holders 14 are adjustable for different heights to accommodate various types of plates. The range through which the segment 4 can pivot is adjustable by means of end stop screws 1 5. Before the next plate is mounted, the fluid pressure actuator 3 is extended and the lever 5 carrying the segment 4 is pivoted outwardly.

Claims

1. A method of orientating a flat article having a shaped edge, such as a ceramic plate, comprising the steps of mounting the article on a rotatable table, positioning one or more pairs of cooperating transmitters and receivers at the edge of the article in positions such that the edge of the article will not obstruct transmission of a signal from a transmitter to its associated receiver when the article is in its correct orientation, and rotating the table until the transmitted signal or all the transmitted signals is or are received at cooperating receivers indicating that the article is correctly orientated, the receivers generating a signal which is used to stop the rotation of the table with the article in this orientation.

2. A method as claimed in Claim 1, in which the transmitters are adapted to direct a jet of air across the edge of the article arid the receivers are pressure sensors operable to produce an output signal when they receive a jet of air from an associated transmitter.

3. A method as claimed in Claim 2, in which the working pressure of the transmitters lies between 0.12 and 0.6 MPa, and the working pressure of the receivers lies between 0.03 and 0.16 MPa.

4. A method as claimed in Claim 1, in which the or each transmitter and receiver is a light source and a photoelectric detector respectively.

5. Apparatus for orientating a flat article having a shaped edge, such as a ceramic plate, comprising a rotatable table for receit- ing the articles, and one or more pairs of cooperating transmitters and receivers nosi tionabe at the edge of the article in positions such that the edge of the article will not interrupt transmission from the or each transmiter to its associated receiver when the article je in the correct orientation and menus for stopping rotation of the table when a signal is received from the or each receiver.

6. Apparatus as claimed in Claim 5, in which the transmitters are adapted to transmit a jet of air across the edge of the article, and the receivers are pressure sensors which produce an output signal when they detect a pressure greater than a determined threshold value.

7. Apparatus as claimed in Claim 6 or Claim 7, in which two transmitters and two receivers are mounted on a segment-shaped support carried at the end of a lever turnable about a fulcrum to move the segment toward or away from the edge of the article.

8. Apparatus as claimed in Claim 7, in which the lever is resiliently biased to a position where the segment is located adjacent the edge of an article on the table and a fluid pressure actuator is provided for displacing the lever to an inoperative position where the segment is spaced away from the edge of an article on the table.

9. Apparatus as claimed in Claim 7 or Claim 8, in which the turning movement of the segment is limited by adjustable end stops.

10. Apparatus for orientating a flat article such as a ceramic plate, substantially as here it before described with reference to the accompanying drawings.

11. A method of orientating a flat article such as a ceramic plate, substantially as hereinbefore described.