The present invention relates generally to article handling apparatus and, more particular- ly, to an apparatus employing an air stream for orienting or classifying articles having surface areas which differ significantly in continuity or roughness. Background Art It is known in the art to use air pres¬ sure in various types of article handling apparatus. In some cases a pressure differential is used to actuate solenoids, pistons, valves or the like. In other, an air stream interacts directly with the article to affect its position or condition. For example, U.S. Patents 3,734,268 and 3,307,678 both disclose apparatus in which articles are handled in accordance with particular characteristics of their configurations by direction of a jet or ^" jets of air at the articles. The air jets are designed to interact with particular parts of the articles to orient them e.g. by physically inverting the articles. Such apparatus would be incapable of distinguishing between articles merely by their surface characteristics if the only difference is that of relative smoothness of the surface. Disclosure of Invention

In accordance with the present invention, as distinguished from the above-discussed prior art, articles are classified or oriented not according to shapes but, rather, by the characteristics of a surface thereof. The present invention makes practical use of a scientific curosity known as "the disc paradox" which is related to Bernoulli's

principle. The present invention recognizes that a stream of air directed at a flat surface produces a different air flow than when the air stream is directed at a rough surface and that, under certain conditions described more ful3,y below, this differ¬ ence in air flow can be used to advantage in the handling and orienting of certain types of articles, particular articles such as the individual parts of a photographic film pack and/or a super 8 film cartridge.

According to the present invention there is provided apparatus for use with a source of air pressure for handling articles, each article having at least one smooth surface and/or at least one rough surface, the apparatus comprising means for transporting the articles along a predetermined path, a member positioned to be engaged by one of the surfaces of each article during such transporta¬ tion and having an air discharge aperture, and means for supplying air under pressure from the source to the aperture to produce an air flow through the aperture (1) to cause those articles having a rough surface facing the air flow to be urged away from the member, and (2) to create laminar air flow between the member and a smooth surface so that those articles having a smooth surface facing the air flow will not be urged away from said member. In a presently preferred embodi¬ ment of the invention, apparatus is provided for handling and orienting generally flat articles wherein each article has a relatively smooth surface on one face and a rough surface on a second face opposed to the first face. Means are provided for transporting the articles standing on one edge while leaning against a flat support

O.Y. y WIP

member. The transported articles advance past an air discharge opening in the support member which directs an air stream against the facing surface of the articles. If the air stream "sees" the rough surface facing the support member, it will blow the article over, rotating it away from the support member about the edge on which the article is standing. If the air stream "sees" the smooth surface facing the support member it provides no resultant force on the article and indeed a vacuum effect may be produced which draws the article toward the support member in its original orienta¬ tion.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described further, by way of example, with reference to the accompany¬ ing drawings, in which:

Figures La, lb and lc show examples of articles having surface characteristics which may be utilized in practicing the present invention,

Figure 2 is a perspective view of an article handling apparatus in accordance with the present invention, depicting a conveyor, article supporting member and an air stream device; Figures 3 and 4 are front elevational views of the apparatus shown in Figure 2;

Figures 5, 6 and 7 are schematic views depicting the physical phenomenon on which the present invention is based; Figure 8 is a perspective view of an article handling apparatus in accordance with a second embodiment of the invention;

Figure 9 depicts articles in a configura¬ tion suitable for use with the apparatus as depicted

in Figure 8; and

Figure 10 is a perspective view of an article handling apparatus in accordance with a third embodiment of the present invention, for separating or classifying articles of different surface types. Best mode for carrying out this invention.

As various types of article handling apparatus are known in the art, the present invention will be directed to elements forming part of or cooperating more directly with apparatus in accordance with the present inven¬ tion. Those specific elements of article handl¬ ing apparatus not shown or described are select- able from those known in the art.

Article handling apparatus perform various functions such as transporting, sorting or orienting articles. The sorting and orienting of articles is particularly necessary in those applications wherein it is desired to automate an assembly process. Designing appropriate apparatus for sorting or orienting articles is, in general, a difficult task because it is necessary to provide mechanical apparatus capable of recognizing the different article types and orientations. Such apparatus generally takes advantage of some characteristic configuration of the article to be handled, such as skirts on lids (U.S. Patent No. 3,734,268) or a bobbin shape (U.S. Patent No. 3,307,678), as discussed above. As a result, apparatus designed for use with one type of article generally is not suitable for handling, sorting or orienting articles of other configurations.

Figure 2 shows an article handling appa- ratus in accordance with one embodiment of the

present invention for use in handling articles generally of the type shown in Figures la, b and c. Each of the articles have a "rough" surface 11, 13 or 17 and a relatively smooth surface 9, 12 or 15 respectively. It will be noted that the smooth surfaces are not perfectly smooth and the rough surfaces are of various types. The meaning of the terms rough and smooth is made more definite below. The rough surface of the article 10 which is shown in Figure 2 is formed of a series of ridges or ribs; however, it will be apparent to those skilled in the art that the rough surface can be formed in many other ways as well, for example see Figures la and lc. In general, the article handling apparatus shown in Figure 2 receives articles 10 in random orientation and sorts the articles 10 into a uniform, predetermined orientation. Means are provided for transporting the articles 10 in the form of a con- veyor 14 comprising a conveyor belt 16 guided by a pair of guide rollers 18 and 20, the guide roller 20 being driven by a motor 22. The conveyor belt 16 is inclined at an angle to a horizontal plane P (Figs. 3 and 4) to cause the articles 10 to lean against a wall or support member in the form of a primary dead plate 26 during transportation. As shown in Figure 2, some of the articles 10 are oriented with their smooth surface 12 toward the primary dead plate 26 (e.g., article 10b), while other articles are oriented with their rough surface 13 toward the primary dead plate 26 (e.g., article 10a). Regard¬ less of the initial orientation, the articles are outputted having a uniform orientation which is indicated by the article 10'. Since all of the articles 10 emerge uniformly oriented, subsequent

handling and assembly of such articles is greatly facilitated. Preferably, plate 26 has a surface positioned substantially perpendicular to said conveyor belt 16. Orientation of the articles 10 is achiev¬ ed by using a single air jet to blow articles away from the primary dead plate 26 or to draw the articles toward the primary dead plate 26, depend¬ ing upon the initial article orientation. In particular, a nozzle 28 is provided in the primary dead plate 26 and is connected to a source of air under pressure. The nozzle 28 may be formed by a hole or aperture in the dead plate 26 or by a separate component which is mounted in an opening of the dead plate 26. The air under pressure pass¬ ing through the nozzle ^* 28 produces an air flow directed away from the dead plate 26. As an article having the orientation of the article 10a passes over the nozzle 28, the air stream impinges upon the rough surface 13 and blows the article 10a_ away from the primary dead plate 26 and against a second support member in the form of a secondary dead plate 30. The article 10a. thus continues to be transported by the conveyor 14 with its smooth surface 12 leaning against the secondary dead plate 30. As the article 10a_ leaves the secondary dead plate 30 it drops onto the conveyor belt 16 in the orientation shown by article 10'. In contrast, as an article having the orientation of article 10b passes in front of the nozzle 28, the emerging air flow causes the article 10b_ to be sucked or drawn against the primary dead plate 26, in a manner more fully described below. The article 10b thus continues to be transported by the conveyor 14 with its smooth surface 12 leaning against the

-BJRE-

OKPI

primary dead plate 26. As the article 10b is transported beyond the primary dead plate 26, it also drops onto the conveyor belt 16 with the orientation as shown by article 10'. The result therefore is that all articles, regardless of their initial orientation, end up on the conveyor belt 16 with the same orientation.

The actual orientation process may be described more clearly with reference to Figures 3 and 4. As shown in Figure 3, the article lθ is leaning on the primary dead plate 26 with its ribbed surface 13 facing the dead plate 26. As the article 10a_ passes over the nozzle 28, which is shown as mounted flush and perpendicular to the dead plate 26, the air flow emerging from the nozzle 28 causes the article 10a_ to be blown over in the direction of arrow 32 against the secondary dead plate 30. Because of the inclination of the conveyor 14 and preferably secondary dead plate 30, the article lO . slides off the dead plate 30 in the direction shown by arrow 34 to the position indicated by 10a . Ultimately, the article lθ may come to rest against a retaining member 36 and be transported to a subsequent work station. Thus, an article lθji having its ribbed surface 13 originally against the primary dead plate 26 will end up on the conveyor belt 16 with the ribbed surface 13 up.

Referring to Figure 4, now consider article 10b_ which is transported by the conveyor

14 and leans against the primary dead plate 26 with its smooth surface 12 toward the dead plate 26. In this orientation, as the article 10b passes over the nozzle 28 a vacuum is created between the smooth

surface 12 of the article 10b and the dead plate 26. (This "vacuum effect" is discussed more fully below.) Unlike the article 10a_, therefore, the article 10b is not blown over against the secondary dead plate 30 but, rather, is sucked down against the primary dead plate 26. As the article 10b is transported by the conveyor belt 16 it drops in the direction indicated beyond arrow 38 onto the conveyor belt 16, now assuming the position shown by article 10b' . As with the article 10a, the article 10b ultimately comes to rest against the retaining member 36 and is transported to a sub¬ sequent work station. The significant factor is that the article 10b, like the article 10a_, ends up on the conveyor belt 16 with their ribbed surface 13 facing up, even though the articles were originally of oppos ite orientation.

It is seen from the discussion above that the same air flow either acts to blow articles over or to draw them towards the dead plate, depending upon whether a rough or a smooth surface faces the air flow respectively. This effect is believed to be related to an example of Bernoulli's principle generally known as the "disc paradox" (for example, General Physics, by William S. Franklin and Barry MacNutt, page 96). The paradox may be exemplified as follows: Shown in Figure 5 is a tube section 40 connected to a support member in the form of flat disc 42. As air under pressure is applied to the tube 40, a flat plate disc 44, surprisingly, is not blown away from the member 42 but, rather, is drawn against the member 42 because of the low pressure created by the rapidly moving air flow between the two discs 42 and 44. If, on the other hand, the flat disc 44 is replaced by a disc 46 as shown in

Figure 6 which has a rough surface 48, the disc 46 is urged away from the disc 42. This result is believed to occur because a vacuum effect is produced when there is laminar air flow between the _^ two discs 42 and 44. The rough or discontinuous surface 48 breaks up this laminar air flow and destroys the Bernoulli condition.

The disc paradox is not limited to articles which have generally planar surfaces. As an example, Figure 7 shows the tube 40 connected to a support member 50 having a curvilinear contour. Spaced from the support member 50 is an article 52 of generally matching, or complementary, curvilinear contour. As air under pressure is applied to the tube 40, a laminar air flow is created between the member 50 and the article 52 which gives rise to a vacuum action causing the article 52 to be drawn down against the support member 50. The important condition is that the contours of the smooth surface of the article and the support member be complementary. It is also important that article 52 be relatively smooth in order to permit laminar air flow to be obtained.

At this point it is appropriate to consider in more detail what is meant by the terms rough and smooth as applied to the surfaces of the article 10. It will be apparent from the discussion above that a rough surface is a surface having a configuration, or texture, which breaks up the laminar air flow between the rough surface and the corresponding support member to such an extent that a vacuum action is not created; in fact, the opposite effect occurs, i.e., the article is blown away from the support member by the air flow. A smooth surface, on the other hand, is a surface which is sufficient-

ly smooth so that the laminar air flow between the article and the support member is not sufficient¬ ly disturbed to cause the article to be urged away from the support member. It should be noted that the definition of a smooth surface is not limited to a surface so smooth as to give rise to a vacuum effect. All that is actually necessary is that the surface be smooth enough to permit sufficient laminar air flow such that the article is not urged away from the support member.

Referring back to Figure 2, it is now seen that the inclination of the conveyor 14 serves two functions. The first function is to permit the articles 10 to lean under the influence of gravity with one surface against the primary dead plate 26 while being transported by the conveyor belt 16. ^• A second function is to enable the apparatus shown in Figure 2 to be operative when used with articles having a "smooth" surface which is not sufficiently smooth to produce a significant vacuum effect, or a resultant vacuum effect at all. Thus, even though the smooth surface of an article tends to break up, to some extent, the laminar air flow produced between the primary dead plate 26 and the articles 10, and therefore the air flow emerg¬ ing from the nozzle 28 exerts a slight pressure upon the article 10, the article 10 is not blown over against the secondary dead plate 30 because the force of gravity acts against the article 10 to maintain the article 10 leaning against the primary dead plate 26. When the rough surface of an article 10 passes in front of an air stream, however, a much greater outward force is exerted against the article 10 and is sufficient to blow the article 10 over onto the secondary dead plate

30. In this case, the outward force exerted by the air stream on the article 10 is greater in magnitude than the force of gravity which tends to hold the article 10 against the primary dead plate 26. It is thus seen that the angle of inclination of the conveyor 14 can be adjusted to compensate for a range of smooth or rough surface types.

There are certain other parameters which may also be adjusted depending upon the particular configuration of the article 10 to be handled. For example, it has been found through experimentation that the article handling apparatus shown in Figure 2 will operate successfully with a range of air pressures and nozzle sizes. The precise range of air pressures and nozzle sizes which are operative are found to. depend to some extent upon the partic¬ ular geometry and surface properties of the article which is being handled. For the article 10 shown in Figure -2 having a ribbed surface 13 wherein the ribs extend about 1/8 of an inch from the article surface, and having a smooth surface 12 which is relatively flat, it has been found that the air pressure applied to the nozzle 28 may vary between about 5 and 15 pounds per square inch, while the nozzle size may vary between about .01 to .10 inches. It will be apparent to those of ordinary skill in the art that these paremeters are inter¬ related. For example, one may be able to compensate for larger nozzle apertures by increasing the air pressure or by redesigning the ribbed configura¬ tion 13 to "catch" more air. Likewise, a low air pressure may be compensated for by decreasing the size of the nozzle aperture. In any event, given a particular geometry and configuration of an

article 10 to be handled, it is a simple matter to experiment with a range of air pressures, nozzle sizes, and conveyor inclinations to determine an operable range of system parameters. Figure 8 shows another embodiment of the present invention for handling articles which have surfaces which are not generally planar. An example of such an article is shown in Figure 9 wherein it is seen that the article has a curvilin- ear, cross section. The article 60 has a smooth surface 62 and a rough surface 64. The apparatus of Figure 8 resembles that of Figure 2 except that the primary dead plate 26, now enumerated 26', has been redesigned to have a surface contour complimentary to the surface contour of the article 60, i.e., both are "S" shaped in cross section. Apart from this difference, the apparatus shown in Figure 8 operates similarly to the apparatus dis¬ closed in Figure 2. The description of such operation need not be repeated. It will be noted that it is only necessary to redesign the primary dead plate 26' and not the secondary dead plate 30. This is because, as discussed in connection with the disc paradox and Figure 7, the primary dead plate should provide a surface which is comple¬ mentary, or matching, in contour to the surface of the article to be handled. It is not necessary that the two surfaces exactly conform in contour, but only that the surfaces be sufficiently matched so as not to destroy the laminar air flow therebetween. As long as laminar air flow is established, the Bernoulli principle will apply and the faster mov¬ ing air between the two surfaces will create a partial vacuum between the primary dead plate 26'

BURE.4

and the article 60, causing the article 60 to be sucked towards the dead plate 26'. An article 60 which passes by the nozzle 28 with an orienta¬ tion such that its rough surface 64 faces the dead plate 26' will, as before, be blown over against the secondary dead plate 30. On the other hand, if the smooth surface 62 faces the dead plate 26', the article 60 is drawn toward the dead plate 26'. The end result is that all articles 60, regardless of their original orientation, end up on the conveyor belt 16 in the orientation of article 60' .

Referring to Figure 10, apparatus is shown in accordance with the present invention for use in separating, rather than orienting, articles of different types. The articles shown in Figure 10 are of two different types. The articles 72 have two smooth surfaces while the articles 73 have two rough surfaces. As the articles are transported by the conveyor 14 past the air flow from the nozzle 28, the articles 72 (which always have a smooth surface facing the air flow) are not blown away from the dead plate 26 but, rather, continue to be transported past the dead plate 26 and fall onto the conveyor in the position indicated by article 72'. The articles 73, which have only rough sur¬ faces, pass the nozzle 28 and are blown away from the dead plate 26 by the air flow. The articles 73 fall off of the conveyor 14, as indicated by article 73', and into a collection bin (not shown). The two different types of articles 72 and 73 are therefore separated according to their surface types, i.e., articles 72 continue to be advanced by the conveyor 14 (see article 72'), while the articles 73 are blown off of the conveyor 14 and

into a collection bin (see article 73').

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected from the scope of the invention as defined in the appended claims.

Oi P