GB2292133A - Article ejection system - Google Patents

Abstract

An ejection system comprising: an infeed mechanism in which articles 10 are introduced into the ejection system by a conveyor means 11 which delivers the articles to but does not extend substantially over an ejection station 13, support means 14 adapted to be moveable in response to an external signal, between a support position in which the articles are supported by the support means as they traverse said ejection station and an unsupport position in which the articles are not supported and thus fall into the ejection station, and a discharge mechanism in which these articles not ejected are transferred from the ejection system to undergo subsequent operations. <IMAGE>

Description

IMPROVED EJECTION SYSTEM Field of the Invention The present invention relates to ejection systems to segregate articles on a production line. It is particularly but not exclusively adapted for use in segregating reject articles on a high speed production line.

Background to the Invention In many production lines there is a need to remove reject or sub-standard articles before the contents of the line enter the packing stage. This can present a very real problem if the line is moving at high speed. One example of how this problem manifests itself and how it is currently managed is in the production of ceramic tiles. These are produced on a production line process and typically at the rate of 300 tiles per minute i.e. 5 tiles per second. Quality control is provided by specially trained people, usually women, who stand over the production line and remove by hand any sub-standard tiles. They literally view every tile and pluck out the ones containing imperfections. This manual method is not without its difficulties: (a) The staff are highly trained and thus command premium pay rates, justifiably so since it is a highly skilled job.

(b) Because of the degree of concentration required these staff can only work for short periods at a time, say 20-30 minutes, and therefore whole teams of these skilled workers are needed if a production line is to run continuously.

(c) If these workers are not available, due to sickness or industrial action for example then the whole line must stop working or else a stack of unscruntinised products will build up.

(d) However highly trained the staff, they can only cope with a certain percentage of our rejects, usually in the order of 10%. Whereas they may be capable of spotting a far higher percentage, they simply cannot move them off the line at a high enough rate. Thus if there is a major problem with the quality of the product the whole line must be closed down, even if the problem has already been seen and rectified in the production stage.

Electronic methods of detecting rejects are now well known and can operate with a high degree of accuracy and at rates up to and in excess of 300 units per minute. However these have not found any significant application, certainly in the ceramic tile industry, because there is no machine or system capable of removing reject articles from a production line moving at those speeds.

The object of the present invention is to provide an ejection system which can operate at those speeds and which allows the automation of the above part of the production process.

Summarv of the Invention According to a first aspect of the present invention, in its broadest sense, there is provided an ejection system comprising: (i) an infeed mechanism in which articles are introduced into the ejection system in a controlled manner, said articles being supported by a conveyor means which delivers the articles to but does not extend substantially over an ejection station; (ii) support means adapted to be moveable between two pre-determined positions, namely a so-called support position in which the articles are supported by the support means as they traverse said ejection station and a so-called unsupport position in which the articles are not supported and thus fall into the ejection station; (iii) a discharge mechanism in which articles are transferred from the ejection system to undergo subsequent operations;; (iv) support means operating mechanism adapted to move the support means into one of two said pre-determined positions in response to an external signal.

Preferably the movement of the support means is synchronised with that of the infeed conveyor means such that the relative movement between the articles and the support means is substantially zero.

Preferably the support means comprises a series of pins adapted to project under the articles as they move along on the conveyor means.

Preferably the pins are mounted in a chain.

Preferably the pins incorporate a head at the end of the pin furthermost from the end which supports the article.

Preferably the pins engage only with the periphery of the articles.

In a particularly preferred embodiment the support means operating mechanism comprises a V-shaped cam wherein the heads of the pins travel through the V-shape which thus dictates the position of the said pins, and wherein the cam moves between two pre-set positions in which the pins are either set in a support position or in an unsupport position.

Brief Description of the Drawings Figure 1 is a plan view of a reject tile ejection system according to the present invention; Figure 2 is a section of the tile ejection system shown in Figure 1 taken along line A-A; Figure 3 is a plan view of a further embodiment which delivers reject items onto a conveyor moving at right angles to the production line; Figure 4 shows a further embodiment in which the pins also act as the conveyor means; Figure 5 shows a diagrammatic sketch of various aspects of a support means operating mechanism.

Description of Preferred Embodiments Figures 1-5 show various embodiments of the present invention. With reference first to Figure 1, this shows a series of ceramic tiles 10 being transported on supporting belts 11. In this example two parallel V-shaped belts running on pulleys are used as shown more clearly in Figure 2.

However any suitable conveyor system can be used including side pressure belts should the nature of the product dictate this. The tiles in this example are held in place by gravity but it is equally possible to take more positive steps to keep the product articles in place by using, for example, compressed air pressure, vacuum, or synchronised belts above and below the article.

The supporting belts 11 terminate at a point 12 adjacent to an ejection station 13. Running parallel to and synchronised with the supporting belts 11 are a series of pins 14 supported by a hollow pin chain 15, an identical row of pins running down each side of the line. The pins have the facility to move from side to side along an axis perpendicular to the chain run. In this example the pins each have a head at the end furthermost from the article to be supported.

The position of the pins is governed by a V-shaped operating cam 16 which can be moved between two pre-set positions. In one position, known as the "support position", the pins are positioned such that they support the product in the absence of the supporting belts 11. In another position, known a the "unsupport position", the product is not supported and as will be seen automatically descends under the force of gravity into the ejection station 13.

The position of the operating cams 16 is dictated by some external detection system shown as 17 in Figure 3. Typically this takes the form on an electronic device which picks up deformities or abnormalities in the product. It could for example be a scanner, comparing images with a standard image in memory, or even sensitive scales that measure weight differences. In any event this detection system provides an output into the present invention to identify which articles have to be ejected from the line. A control mechanism within the system adjusts the cams 16 into the appropriate position as each tile passes by. Thus as each tile 10 reaches the eject station 13 it is either supported safely across the station or allowed to descend into the station as dictated by external detection system.

A variety of alternatives to the cam mechanism are possible. For example belting may be used with attachments for this purpose. Furthermore, the pins need not necessarily be headed, in which case a guide would simply push the pins into the appropriate confirmation.

The pins normally support only the extreme edges of the product article, as shown in figures 1-3. However, by having longer pins 31 as shown in figure 4 the pins could be arranged to extend substantially across the whole of the article. This modification is particularly relevant where the article is not rectangular as in the case of a circular compact disc for example.

In a further embodiment the support belts could be dispensed with and the articles placed directly onto the pins 14, providing they are first set in the support position.

The pins are positioned just below the level of the article 10 as it sits on the supporting belts 11. In this way the wear on the pins is minimised and the article is simply deposited on the pins, if they are in the support position, on entry to the ejection station. As well as minimising pin wear this also eliminates the danger of marking delicate articles.

The operating cam 16 is shown in more detail in Figure 5. This effectively shows a void 18 through which the head of each pin 14 may pass. The cam is of a multi-layer sandwich-type construction and has a wide entry portion 21 created by jaws 19 and 20 designed to catch the pin head whatever the previous position of the pin.

The ejection station 13 consists of an area where there is no supporting belt and under which there may be a waste pin, a conveyor travelling in a different direction to the original production line (as shown in Figure 3), a collating device or the like. In practice if the pins are in the unsupport position when an articles reaches the ejection station it simply falls below the level of the opposing support belt and hits a backstop 23. The article then descends into whatever mechanism is placed beneath the ejection station.

In this example the articles simply fall under the force of gravity but a stream of compressed air or other mechanism could be used to assist lighter objects.

This arrangement has the added advantage that if there is a problem with the production line and all the articles need to be diverted this is easily achieved, providing the mechanism beneath the ejection station can cope with the volume of articles.

For ease of operation the pins are usually pushed aside, i.e. into the unsupport position, for the return journey to the start of the process since the hollow pin chain 15 is in the form of a continuous loop.

In summary, an article to be ejected is detected by some external means and an instruction given to the operating cam to position the support pins adjacent to that particular article in the unsupport position. The article then falls out of the system through the ejection station. The pins are very rarely used, only when passing over the ejection station and never touch the uppermost face of the tile or article.

It is possible to use such a system to grade rejects by placing a number of ejection stations in series. Either a single external detection system or a series of detection systems can be used to set the pins to the appropriate setting for each ejection station.

The use of the present invention is not limited to handling reject articles. It can be used for segregation articles of any description on a production line.

Typical examples would be quality control in the food industry, or with records and CD's It could also find use in egg grading where all items are perfectly good.

Claims (9)

Claims

1. An ejection system comprising: (i) an infeed mechanism in which articles are introduced into the ejection system in a controlled manner, said articles being supported by a conveyor means which delivers the articles to but does not extend substantially over an ejection station; (ii) support means adapted to be moveable between two positions, namely a so-called support position in which the articles are supported by the support means as they traverse said ejection station and a so-called unsupport position in which the articles are not supported and thus fall into the ejection station; (iii) a discharge mechanism in which articles are transferred from the ejection system to undergo subsequent operations; (iv) support means operating mechanism adapted to move the support means into one of two pre-determined positions in response to an external signal.

2. An ejection system as claimed in Claim 1 wherein the movement of the support means is synchronised with that of the infeed conveyor means such that the relative movement between the articles and the support means is substantially zero.

3. An ejection system as claimed in Claim 1 or Claim 2 wherein the support means comprises a series of pins adapted to project under the articles as they move along on the conveyor means.

4. An ejection system as claimed in Claim 3 wherein the pins are mounted in a chain.

5. An ejection system as claimed in Claim 3 or Claim 4 wherein the pins incorporate a head at the end of the pin furthermost from the end which supports the article.

6. An ejection system as claimed in any of Claims 3-5 wherein the pins engage only with the periphery of the articles.

7. An ejection system as claimed in Claim 5 wherein the support means operating mechanism comprises a V-shaped cam wherein the heads of the pins travel through the V-shape which thus dictates the position of the said pins, and wherein the cam moves between two pre-set positions in which the pins are either set in a support position or in an unsupport position.

8. An ejection system as claimed in Claim 1 wherein the support means also serves as the conveyor means in order to feed articles into the system.

9. An ejection system substantially as herein described with reference to and as illustrated in any combination of the accompanying drawings.