GB2079235A - Article Transfer System - Google Patents

Abstract

In a continuous conveyor circuit utilizing a plurality of suspended pallet or working supporting buckets or platforms (28) that are pendulant, a system is provided to avoid oscillation of the buckets not only in the straight runs of the conveyor chains (24) but also as the buckets traverse the curved regions around chain sprockets (12,20). A separate stabilizer chain (52), spaced from the main drive conveyor chains (24) is parallel in its path to the main drive chain, and bucket sprockets (50) at each bucket are engaged peripherally with the main drive chain. The stabilizer chain (52) is driven at the same linear speed as the drive chains (24) so that, as the bucket sprockets (50) move around a curved path, they are controlled to maintain proper consistent orientation of the buckets. <IMAGE>

Description

SPECIFICATION Article Transfer System The invention relates to article transfer systems and is useful in systems in which elevators are used to move articles vertically on suspended trays or buckets.

In the general field of article transfer systems, a commonly used device is a bucket elevator. In essence, these devices employ parallel endless chain loops operating in a generally vertical direction; between these chain loops are suspended, through suitable pivots on the chain, pendulant article carriers or buckets. Where these buckets traverse straight runs or flights of the chain, it is possible to add relatively simple means to provide bucket stability, i.e., to keep the buckets from swinging. However, where the chains traverse curved path or their parts go around sprockets, the providing of bucket stability becomes more difficult.

It is an object of this invention to provide a system of stabilization which is simple, relatively inexpensive, an theoretically perfect, i.e., any small lack of stability is created by mechanical imperfections rather than in the theoretical concept of the system.

Other article carrier systems employing chains, or their equivalents, move articles from point to point. Some of these require that the articles move parallel to themselves around linear and curved paths. In the generally accepted kinematic sense, moving an object parallel to itself along a curvilinear path is referred to as translation.

It is another object of this invention to provide a system for moving articles in translation through any predetermined closed loop path.

The invention resides in an article transfer system comprising one or more loops of flexible transporting drive means which are movably supported in a structural frame and driven by prime mover means and on which are rotatably mounted multiple article carrying members, each on a respective pivot axis substantially intersecting the flexural axis of said flexible transporting drive means, and means for stabilizing said article carrying members for movement in translation, whereby said article carrying members are stabilized in a substantially constant angular orientation with respect to fixed space as said article carrying members are moved along a predetermined curved and straight path portions of said flexible transporting drive means, said means for stablizing comprising a loop flexible stablizing means mounted for movement in said frame along a path substantially uniformly distant from the path of said flexible transporting drive means, and moving at substantially the same linear speed as said flexible transporting drive means, and a circular stabilizing member mounted on each article carrying member, concentrically about the respective pivot axis of said member, and having its circumference formed to engage in a driving relationship with said flexible stablizing means.

The invention will be further described by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side elevation, partially schematic, of a bucket elevator employing the present invention, Figure 2 is a section taken on line 2-2 of Figure 1, Figure 3 is a section taken on line 3-3 of Figure 1, Figure 4 is a kinematic diagram for use with the description of the theoretical mathematical principles of operation of the elevator, Figure 5 is a side elevation, partially schematic, of a more complex article transfer system employing this invention (it may also be considered as a plan view for some applications of the invention), Figure 6 is a section taken on line 6-6 of Figure 5, Figure 7 is a detail variation on the sectional view in Figure 6, Figure 8 is a section taken on line 8-8 of Figure 5, Figure 9 is a section of a modification, corresponding to a section taken on line 9-9 of Figure 5, and Figure 10 is a section taken on line 10-10 of Figure 5, but corresponding to an alternative to the section of Figure 9.

Figure 1 shows a typical bucket elevator employing two straight vertical chain flights and two 1 800 reversals as the suspending or primary chain traverses an upper and lower sprocket pair.

Referring to Figures 1 to 3, two sideplates 2 and 3 are held in parallel alignment by spacers 4 to comprise a frame for the entire mechanism. A lower sprocket shaft 6 is journalled in the sideplate 2 through a pillow block 8: at the other sideplate 3, this shaft 6 is supported and driven by a suitable drive mechanism 10 shown by outline only. This drive mechanism 10 may comprise an electric motor and suitable gear reducer for a constant velocity drive of the system; or, for intermittent indexing of the system, the drive mechanism may be a mechanism such as shown in U.S.A Patent No.

3,789,676 or U.S.A. Patent No. 3,859,862. Two lower elevator sprockets 1 2 are mounted on and rotate with the shaft 6.

Two colinear stub shafts 14 and 1 6 are mounted in a U frame 18 which is bolted to the sideplates 2 and 3; two upper elevator sprockets 20 are journalled on the shafts 14 and 16 through bearings 22. Two primary chain strands 24 form continuous loops, with each chain passing around one upper sprocket 20 and one lower sprocket 12. The straight flights of the chain pass through channel guides 26 (Figures 2 and 3) mounted on the sideplates 2 and 3.

A series of article carrying buckets 28 are pivotally suspended from the primarychains through hinge pins 30; these hinge pins, and the buckets 28 carried thereby are guided by rollers 32 which are closely fitted to the channel guides 26. Each bucket 28 is comprised of two hangers 34, a crossbeam 36, and article support arms 38.

This construction of the buckets 28 is illustrative only and is of the type utilized in UK Patent applications No. 7917950 (Serial No.

2023524A) and No. 7924568 (Serial No.

2026972A). An additional stabilizing roller 40 is added to one hanger 34 of each bucket 28 directly below a hinge 30. This roller is coplanar with one of the rollers 32, and also moves through the channel guides 26.

It can be seen, therefore, that, with the elements described up to this point, the buckets 28 are stablized, i.e., prevented from swinging in a pendulum fashion about the hinge pins 30, by a roller 40 in the channel guide, as the buckets 28 traverse the straight chain flights. However, as that portion of the primary chains 24 carrying given hinge pins 30 traverses either the upper sprockets 20 or lower sprockets 12, a given bucket 28 is free to swing freely, i.e., pendulate, about those hinge pins 30.

The additional elements to be described prevent the aforesaid free swinging of the buckets 28 as they traverse the sprockets 12 and 20. A bucket stabilizing sprocket 50 is mounted on one side of each bucket 28 concentric with the hinge pin 30. All of the sprockets 50 engage one strand of a continuous multistrand stabilizing chain 52; the strands are parallel and directly adjacent each other. The other strand of the stabilizing chain 52 passes around a lower stabilizing sprocket 54 and an upper stabilizing sprocket 56. The upper stabilizing sprocket 56 is mounted on the stub shaft 14 through bearings 58 and is concentric with the upper sprockets 20. The lower stabilizing sprocket 54 is similarlyjournalled on the lower shaft 6 and is concentric with the lower sprockets 12.The straight flights of the stabilizing chain 52 are maintained in contact with the bucket sprockets 50 by guide rails 60 supported from the side plate 2 by brackets 62.

In order for a bucket sprocket 50 to remain in mesh with its corresponding strand of the stabilizing chain 52 as the other strand of the stabilizing chain 52 passes around one of the sprockets 54 or 56, it can be seen that the pitch radius of the primary chain sprocket 12 or 20 inust be the sum of the pitch radius of a bucket sprocket 50 and the pitch radius ofthe corresponding stabilizing sprocket 54 or 56.

The operation of this system is conventional as concerns the stabilization of the buckets as they traverse the straight portions of the chain. As the drive mechanism 10 rotates the lower shaft 6, the primary chains 24 are driven by the lower sprockets 12 which in turn cause the upper sprockets 20 to rotate at the same pitch line velocity. The buckets 28 suspended from the chains 24move with it, and those buckets 28 moving along the straight flights are guided or stabilized from oscillation by the action of the stabilizer roller 40 operating in the channel guide 26. This portion of the system is conventional.

The bucket sprockets 50 on those buckets 28 which are stabilized on their straight flights by the rollers 40 cannot rotate with respect to the buckets 28 and therefore cause the stabilizing chain 52 to move with the bucket sprockets 50 and buckets 28 along the straight flights. It can be seen, therefore, that the stabilizing chain 52 will be moved linearly by the sprockets 50 at the same linear or pitch line velocity as that of the primary chain 24. Accordingly, as a result of this drive, the upper stabilizing sprocket 56 and lower stabilizing sprocket 54 will rotate at a higher angular velocity than the angular velocities of the upper sprockets 20 and lower sprockets 12.

As a given bucket 28 moves out of a straight flight and its supporting hinge pin 30 moves in a circular path around one of the primary chain sprockets 12 or 20, that bucket 28 will be stabilized and caused to translate, i.e., move parallel to itself, in space in a translatory path due to the relative rotation of the bucket sprocket 50 which is driven by the stabilizing chain 52, moving at the same linear speed as the primary chain 24.

Figure 4 is a schematic kinematic diagram showing the motion characteristics of the stabilization system as a given bucket traverses some portion of a circular translatory path as it moves around the upper sprockets 20. Referring to Figure 4: R,=pitch radius, upper sprocket 20 R2=pitch radius, upper stabilizing sprocket 56 R3=pitch radius, buckets procket 50 All elements carry the suffix "A" at the position where a given bucket has reached the end of a straight flight and is starting to move around the sprocket 20. After the sprocket 20 has rotated through some arbitrary angle 0, a second position of the elements is reached and they carry the suffix "B".In the "A" position, the point of mutual tangency between the stabilizing chain 52, bucket sprocket 50, and upper stabilizing sprocket 56, is defined as PA on the stabilizing sprocket 56 and as QA on the bucket sprocket 50. After the upper sprocket 20 has rotated through the angle 0 to position "B", the stabilizing sprocket 56 has rotated through some larger angle 0 and the point PA has reached a position Ps. During this same movement, the point QA on the bucket sprocket has reached the position QB It can be seen that for the bucket 28B to be parallel to the bucket 28A, it is necessary that the arc subtended by angle p (from PB to the new point of mutual tangency) be identical in length to the length of the arc subtended by angle a (from Q5 to the new point of mutual tangency); i.e., R2=R3a Since P=l-e and (for parallel movement) Then Then R2(0~0)=R30 R20=(R2+R3)0 Now if R1=R2+R3 as is required for mechanical operation with sprockets 20 and 56 concentric, then R20=R, 0 R2 is seen to be the distance the stabilizing chain 52 has moved from position A to position B and R10 is seen to be the distance the primary chain 24 has moved during this same interval.If both chains move the same distance interval along their pitch line during a given arbitrary time interval, they are moving at the same velocity.

Therefore, for the buckets to move parallel to themselves, i.e., to be stabilized as they move around a sprocket, the only constraint is that the primary chain and the stabilizing chain move at the same velocity. This is automatically the case when the stabilizing chain is driven by those buckets and bucket sprockets that are moving along the straight flights. It is interesting to note that the magnitudes of R2and R3 may be varied to suit mechanical convenience, without affecting the relative chain velocities, provided only that R2+R3=R1 or R3=R1-R which is achieved by concentricity between the primary chain sprockets and the stabilizing chain sprockets.

An analogous analysis shows that the pitch radius of the stabilizing chain sprocket 56 may be larger than the pitch radius of the primary chain sprocket and the buckets will again be stabilized, provided again that the primary chain and stabilizing chain move at the same pitch line velocity and that the primary chain sprockets and stabilizing chain sprockets be concentric. In this situation, however, R3=R2R,; i.e., the bucket sprocket pitch radius is the difference between the pitch radii of the primary chain sprocket and the stabilizing chain sprocket with the latter being the larger.In the situation of Figure 4, R3=R1-R2, this can also be described as requiring that the pitch radius of the bucket sprocket be the difference between the pitch radii of the primary chain sprocket and the stabilizing chain sprocket with the former being the larger.

In the general situation then, the buckets can be moved along any primary chain path and around any number of primary sprockets of various diameters and be stabilized, i.e., kept moving parallel to themselves, by a bucket sprocket mounted on each bucket and in engagement with a stabilizing chain which moves parallel to and equidistant from the primary chain path, provided that the distance between the two chain paths is equal to the pitch radius of the bucket sprockets, and that the two chains move at identical pitch line velocities.

Referring again to Figure 4, it can be seen that the kinematic characteristics of the bucket movement around the sprocket 20, i.e., any bucket moves parallel to itself, remains the same independent of the orientation of the diagram in space. The buckets are stabilized in the same manner if the diagram is inverted to represent the situation occurring at the lower sprocket 1 2 where the buckets are also restrained from oscillation by this mechanism. It will be appreciated that the buckets not only are caused to move in proper orientation around a curve, but they are also mechanically fixed in the proper position because of the contact of the sprockets with the two chains.

An illustrative general system is shown in Figure 5 which also employs concave as well as convex curved flights of the chains. A structural frame 70, shown in outline, has journalled therein five shafts 72, 74, 76, 78 and 80; these shafts in turn support the primary chain sprockets 82, 84, 86, 88 and 90 respectively. Two strands of primary chain 92 are supported and guided on the sprockets 82-90 as shown. A series of buckets or other carriers are pivotally mounted and carried by the chains 92 as described in the embodiment of Figures 1 to 3; they are schematically represented by a marker line 94 on each of the bucket sprockets 96 mounted concentrically with the pivot axis of each bucket or carrier.As before each bucket sprocket 96, which now also represents the bucket or carrier on which it is mounted, is in mesh with a stabilizing chain 98.

This stabilizing chain 98 is equidistant from the primary chain 92 and is supported and guided by sprockets 100, 102,104 and 106 which are journalled on shafts 72, 74, 76 and 80 respectively. The guide for the chain 98 around shaft 78 will be later described.

As the stabilizing chain 98 moves equidistant to primary chain 92 on sprocket 88 on shaft 78, it is guided by means other than a sprocket as will subsequently be explained. It will be noted that the constant distance between the primary chain 92 and the stabilizing chain 98 is equal to the pitch radius of the bucket sprockets 96 as is required (FIGURE 4). This is achieved by having the difference between the pitch radius of the primary sprockets 82, 84, 86 and 90 and the pitch radius of their corresponding stabilizing sprockets journalled on a common shaft, i.e.

sprockets 100, 102, 104 and 106 respectively, equal to the pitch radius of the bucket sprockets.

It can be seen that the pitch radii of the primary sprockets 82, 84, 86 and 90 are unequal; but for each of these sprockets and pitch radius of its associated and concentric stabilizing sprockets is less than the pitch radius of the primary sprocket by an amount equal to the pitch radius of the bucket sprockets 96, hence the equidistant spacing between the chains 92 and 98.

Whereas in the embodiments of FIGURES 1 to 3, the equal chain velocity between the primary chain and the stabilizing chain was self generated through the driving action of the bucket sprockets on the stabilizing chain on the long straight chain flights, here in the embodiment of FIGURE 5, a direct drive system for each chain system is employed.

Referring to FIGURES 5 and 6, the stabilizing sprocket 100 is connected to a coupling sleeve 108 which in turn is connected to a drive sprocket 110. Sprockets 100 and 110 and sleeve 108 rotate as an assembly on shaft 72 supported by bearings 112. Sprocket 110 is driven through a chain 114 from one section of a tandem drive sprocket 11 6 mounted on the output shaft 118 of a gear reducer 120, which is driven in turn by an electric motor 122 through a coupling 124.

The corresponding primary sprocket 82 is directly connected to its drive sprocket 126; this sprocket pair 82, 126 is journalled on the sleeve 108 through bearings 128, and therefore rotates concentrically with the sprocket pair 100, 110.

The sprocket 126 is driven through a chain 130 from the other sprocket of the tandem sprocket 11 6. With the proportions shown in FIGURE 6, as the output shaft 11 8 rotates, the tandem sprocket 116 drives sprockets 110 and 126 through chain 114 and 130 respectively; and stabilizing sprocket 100 and primary sprocket 82, though rotating at different angular velocities, drive primary chain 92 and stabilizing chain 98 at the same linear or pitch line velocity. With this arrangement, both chains 92 and 98 are directly driven by the prime mover system and not dependent on the slave type drive system of FIGURES 1 3. It can also be seen that only one primary chain strand 92 is so driveri.Where multiple primary chain strands 92 are employed, as is conventionally, but not necessarily the case, such a cross connection can be accomplished by fastening any set of primary sprockets, such as 84, directly to their mounting shaft, such as 74, and then in turn journalling such a shaft in the frame 70. Clearly, the associated stabilizing sprocket 102 is still journalled on the shaft 74.

A third means of achieving identical pitch line velocity of chains 92 and 98 is shown in Figure 7 which is a variation of Figure 6. In this instance, it is defined that the primary chains 92 are driven at one of the other shafts 74, 76, 78 or 80 using an arrangement functionally identical to that shown in FIGURE 3 with drive shaft 6 and sprockets 12 mounted thereon. It will be understood that the mechanism of FIGURE 7 replaces the drive systems of FIGURE 6 comprising elements 11 6- 124. The chain 130 engages one sprocket of an idling tandem sprocket 132 journalled on a countershaft 134 through bearings 136; the other half of tandem sprocket 1 32 is engaged by chain 114, and the countershaft 134 is mounted to the frame 70 and to an auxiliary bracket 138 also mounted to frame 70 using conventional practice.

With this in mind, it can be seen that as the primary chain 92 moves, as separately driven at one of the other shafts, this movement drives sprocket 82 and its coupled sprocket 126; this in turn drives the tandem idler sprocket 132 through chain 130, then back through chain 114 to sprocket 110 to stabilizing sprocket 100 which then drives stabilizing chain 98. Again, with the proportions shown in this countershaft drive system, FIGURE 6 plus FIGURE 7, both chains 92 and 98 move at the same linear velocity.

It will be recalled that at shaft 78 of FIGURE 5, no stabilizing sprocket is shown. In this and the previous embodiment, the stabilizing chain has been shown as operating between the two primary chain strands; this will be defined as an internal stabilizing system. With such an internal system, a concave condition, such as about shaft 78, where a stabilizing sprocket would be larger than its associated primary sprocket, there would arise an interference between the stabilizing sprocket and the hinge support pins for the buckets. Therefore, a sprocketless guide system for the stabilizing chain must be used for such a combination of conditions. Such an illustrative system is shown in Figure 8.

Referring to FIGURE 8, one (of two) primary sprockets 88 is mounted on the shaft 78 which is journalled in the frame 70 through a pillow block 140. It will be understood that the other end of shaft 78 mounts a second sprocket 88 and is similarly journalled in the frame. Sprockets 88 support and guide the primary chains 92 in a conventional manner. The stabilizing chain 98 is guided around its concave path by a stationary arcuate chain guide 142 supported from the frame 70 by brackets 144. This chain guide 142, shown in section in FIGURE 8, is formed into a true arc having its center on the axis of shaft 78.

The length of this arc is slightly greater at each end than the arcuate path of the stabilizing chain 98 as it traverses around the shaft 78. In effect, this chain guide is analogous to a sprocket but creates no mechanical interference with the bucket hinge pins.

The embodiment of FIGURE 5 has been described above as a side view of a bucket carrier system comparable but more complex than the simplest elevator of FIGURE 1. FIGURE 5 may also be viewed as a plan view of an article or fixture carrier operating in a horizontal plane and moving workpieces or fixtures in a predetermined path, such as between work stations, load, unload, stations, etc., but having the requirement that the workpieces or fixtures always move parallel to themselves through straight and curved paths, i.e., by translations. Considering FIGURE 5 as such as plan view, two alternative sections are taken through shaft 74 to illustrate the construction, as shown in FIGURES 9 and 10.

Referring to FIGURE 9, the shaft 74 is mounted in the frame 70A through bearings 150; this frame 70A is smaller than the frame 70 to permit access to the articles being transported. The two primary sprockets 84 are mounted on the shaft 74 and support and guide primary chains 92.

Chain adaptors 1 52 are intermittently spaced on the chains 92. Within each adaptor 1 52 is journalled a flanged fixture support shaft 1 54 through a bearing 1 56. The "bucket" sprocket 96 is mounted on the shaft 1 54 and meshes with the stabilizing chain 98 which operates on the stabilizing sprocket 102 journalled on shaft 74 through bearings 1 58. The upper portion of the shaft 1 54 is formed into a flange 1 60 on which is mounted a fixture 1 62 adapted to carry a workpiece or other article for movement in translation along the curved and linear path of chain 92.

An alternate structural arrangement for the guidance of the primary chains 92 and the stabilizing chain 98 is shown in FIGURE 10 which is taken on the same section line of FIGURE 5, again considering FIGURE 5 as being a plan view of a horizontal transport system. The shaft 74 is again journalled in the frame 70A through bearings 150; two sprockets 84 are mounted on the shaft 74 and operate with the two primary chains 92. A chainadaptor 170 is mounted on the chains 92 and supports a stepped shaft 1 72 through bearings 1 74. The "bucket" sprocket 96 is mounted on shaft 172 and meshes with the stabilizing chain 98 which is guided by the stabilizing sprocket 102 journalled on the shaft 74 through bearings 176.The upper end of the shaft 172 is formed into a flange 178 on which is again mounted a fixture 162 adapted to carry a workpiece or other article for movement in translation.

By comparing the alternative constructions of FIGURES 9 and 10, it can be seen that the only difference is in the position of the stabilizing chain 98 relative to the primary chains 92; in FIGURE 9, the stabilizing chain 98 lies on the opposite side of the primary chains 92 from the position of the fixture 162, whereas, in FIGURE 10, it lies on the same side as the fixture 1 62. In either case, the stabilizing chain 98 lies external to the primary chains 92 as distinguished from the embodiment of FIGURES 1 to 3 in which the stabilizing chain 98 lies between or internal to the primary chains 92.In some situations in which the stabilizing chain lies external to the primary chains, it becomes possible to use sprockets for all the turns of the stabilizing chain, even though the radius of the curve followed by the stabilizing chain is larger than the radius of the curve followed by the primary chains. This is not so when the stabilizing chain is internal to the primary chains in which case a larger stabilizing chain radius requires a chain guide rather than a sprocket, as shown in FIGURE 8.

From the descriptions of the foregoing embodiments, it can be seen that the essential elements of this invention comprise a series of buckets or article carriers rotatably (usually pendulantly) mounted on a pair of primary chains, substantially intersecting the flexural axis of these chains, and moving along a path comprised of straight and curved lines. On each such carrier, a circular bucket sprocket is mounted concentric with the axis of rotation, and this sprocket engages or is in mesh with a stabilizing chain moving parallel to and at a substantially identical linear or pitch line velocity as that of the primary chains. The angular velocities of the sprockets used to guide the chains around the curved paths will not be identical, but their pitch line velocities will be.Three distinct means for moving the stabilizing chain at the same velocity as the primary chain are illustrated; when the straight portions of the chain flights are sufficiently long, the buckets or carriers may be guided and stabilised by external guides in which case the bucket or carrier mounted sprockets may themselves propel the stabilizing chains as required (FIGURES 1, 2, 3); or the primary drive system may independently drive the primary and stabilizing chains at identical velocities (FIGURE 6); or the primary chains, driven at some other point, may drive the stabilizing chain through a countershaft and sprocket arrangement (FIGURE 7). Other systems, involving gear trains, servo systems and comparable mechanisms could obviously be employed to achieve the desired objective; i.e., the movement of the stabilizing chain at the same velocity as the primary chains.

Although conventional mechanical chains are shown in the various embodiments, it will be understood that various other flexible drive means could be used in their place, such as, ribbed or cogged belts.

While the sprockets associated with the stabilizing chains are shown as being concentric with the sprockets of the primary chain at all chain curvature points, it will be understood that some slight but meaningful lack of concentricity may be utilized, primarily as a means of chain tightening to keep all chain loops equally tight.

Claims (9)

Claims

1. An article transfer system comprising one or more loops of flexible transporting drive means " which are movably supported in a structural frame and driven by prime mover means and on which are rotatably mounted multiple article carrying members, each on a respective pivot axis substantially intersecting the flexural axis of said flexible transporting drive means, and means for stabilizing said article carrying members for movement in translation, whereby said article carrying members are stabilized in a substantially constant angular orientation with respect to fixed space as said article carrying members are moved along a predetermined curved and straight path portions of said flexible transporting drive means, said means for stabilizing comprising a loop of flexible stabilizing means mounted for movement in said frame along a path substantially uniformly distant from the path of said flexible transporting drive means, and moving at substantially the same linear speed as said flexible transporting drive means, and a circular stabilizing member mounted on each article carrying member, concentrically about the respective pivot axis of said member, and having its circumference formed to engage in a driving relationship with said flexible stabilizing means.

2. A mechanism as claimed in claim 1, in which said flexible stabilizing means is driven by said circular stabilizing members on those of said article carrying members for the time being moving along the straight path portions of said flexible transporting drive means.

3. A mechanism as claimed in claim 2, in which guide means is disposed along the straight path portions of said flexible transporting drive means, and a follower means engaging said guide means is provided on each article carrying member at a point spaced from the pivot axis of said member to establish an interdriving relationship betwean said flexible stabilizing means and said flexible transporting means.

4. A mechanism as claimed in claim 1, in which said flexible stabilizing means is drivem from said prime mover means, not via said flexible transporting drive means.

5. A mechanism as claimed in claim 1, in which said flexible stabilizing means is driven by an intermediate mechanism itself driven by said flexible transporting drive means.

6. A mechanism as claimed in any preceding claim in which said flexible transporting drive means comprises one or more multiple link chains, supported in said structural frame by multiple sprockets journalled therein.

7. A mechanism as claimed in any preceding claim, in which said flexible stabilizing means comprises a multiple link chain and each of said circular stabilizing members comprises a sprocket engaging said multiple link chain.

8. A mechanism as claimed in any preceding claim, in which the radius of said circular stabilizing member is substantially equal to the uniform spacing between said flexible transporting drive means and said flexible stabilizing means.

9. An article transfer system, constructed and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.