The present invention relates to an arrangement for a conveyor track for mutually identical objects of variable sizes comprising a hollow track body with a flat upper surface and an endless conveyor belt, which runs between the ends of the track body with its one advancing part on the aforementioned upper surface and with its other returning part introduced into the track body, in conjunction with which the conveyor track has at least two sections which form an angle with one another, and in conjunction with which the objects are transported resting on the aforementioned advancing part of the conveyor track and are guided laterally by longitudinal rails operatively attached to the track body, the mutual distance between which rails is adjustable to the size of the objects in order, by so doing, to prevent the occurrence of blockages on the track, and in conjunction with which the ends of the rails in an area around the aforementioned angle between the sections of the track are executed with partially overlapping pairs of elements, which form rail curves to either side of the conveyor track and are capable of moving in relation to one another, so that adjustment of the mutual distance between the rails can also be carried out in areas where two track sections form an angle with one another.

In order to prevent the objects which are being transported via the conveyor track from becoming blocked along its length, it is important to ensure that the objects are transported in a line one after the other and are not given the opportunity to become wedged between one another and the rails. For this purpose, the distance between the rails must thus also be adjusted in the area where the track sections meet, so that it is slightly larger than the transverse dimension of the object or, in the case of circular objects, their diameter.

In a previously disclosed conveyor track, the rails are supported by brackets which are securely bolted to the track body. In order to be able to adjust the distance between the rails along the straight sections, the brackets are equipped with slotted holes which facilitate the desired adjustability of the aforement oned distance. In the area around the point at which the sections meet, it is necessary for a certain section

area to have two associated rail curves with different radii of curvature. Up to four pairs of curves will perhaps be required in order to cover a desired range of distances within which the transverse dimension or the diameter of the object is permitted to vary.

It is clear that it is difficult and labour-intensive, and thus expensive, to carry out the adjustment of a new rail separation dimension. In view of the difficult and time-consuming nature of the adjustment, this operation is very often neglected, which can give rise to operating failures and resulting loss of production.

Previously disclosed via US, A, 1877334 is the use in conjunction with an angled conveyor track- of rails which, in the area around an angle between the sections of the track, are executed at their ends with pairs of interacting elements. These elements are executed so that one element can be inserted into the other, which permits the width of the conveyor track, including in curves, to be changed without difficulty. This solution does not, however, permit the radius of curvature of the conveyor track to be adapted to the new track width, which can result in blockages of objects which are being transported by means of the conveyor track in the angled area.

The object of the present invention is primarily to make available an arrangement of the kind described by way of introduction in which, by adjusting the mutual distance between the side rails, corresponding adjustment is obtained automatically in the area around the point at which the track sections meet, whilst retaining essentially arc-shaped curvature of the rails, as well as an adaptation of the radius of curvature of the arc where the angle between the aforementioned sect ons may also vary. This is achieved in that the aforementioned elements are shaped in such a way that they are so arranged, as the value of the angle between the track sections varies, as to interact in such a way that the aforementioned mutual distance is maintained, and that they are so arranged, in conjunction with an adjustment of the mutual distance, as to interact in order to bring about adaptation of the radii of curvature of the rail curves.

A further object of the invention is to permit the rapid and accurate adjustment of the mutual distance between side rails, which is achieved in that the operative connection between the track body and the longitudinal rails comprises, in each of at least two points along a section of track, a shaft rotatably mounted in the track body and across it, which shaft has a thread at its ends projecting beyond the track body, onto which thread a bracket supporting the respective rail is threaded, in that the threads run in opposite directions to one another, in that the shafts are mechanically linked to and synchronized with one another, for example by means of sprockets arranged on the shafts and chains running over the sprockets, and in that a device for causing it to rotate is attached to one of the shafts.

Given that the necessary adjustment required in order to transport objects having a different dimension relative to the earlier dimension is very readily executed, production of objects can take place in the requisite numbers, i.e. a costly buffer is no longer necessary.

A preferred embodiment of the present invention is characterized in that the aforementioned pairs of elements are arranged partially overlapping one another and in such a way that an object is able to pass first along the delimiting surface of one element facing towards the object, and then along the corresponding delimiting surfaces of the second element, in conjunction with which the aforementioned delimiting surfaces together describe the arc of a circle, the arc angle of which is approximately the same as the angle between the sections of the track.

The invention is described below in greater detail with reference to the accompanying drawing, in which Fig. 1 illustrates schematically a cross- section through a conveyor track in accordance with the invention, the side rails of which are adjustable manually or by means of a motor. Figures 2a, 2b and 3a, 3b illustrate conveyor tracks in accordance with the invention, two sections of which form angles of 90 ^* and 180 ^* respectively with one another, whereby Figures 2a, 3a illustrate the transport of objects of comparatively small diameter, and Figures 2b, 3b illustrate the transport of objects of comparatively large diameter.

The designation 1 is used generally in the drawing in respect of a conveyor track with two track sections la, lb which form angles with one another, respectively 90 ^* and 180 ^* in the illustrated examples.

The conveyor track 1 comprises a hollow track body 2 and a conveyor track 3 which extends between the ends of the track body 2. The track body 2 has a rectangular, preferably square cross-section, which gives the track body 2 a flat upper surface 2a. The conveyor track 3 is constructed from interacting links of a conventional kind and runs over guide rollers arranged at the ends of the track body, one of which guide rollers at least is driven by a motor, preferably an electric motor. The advancing part 3a of the conveyor track 3 runs on the flat upper surface 2a of the track body 2, and its return part 3b is routed inside the track body 2. In the area in which the track sections la, lb meet, the track runs in a curve guided by a guide disk 4.

The designation A is used in the drawing in respect of objects which are transported resting on the advancing part 3a of the conveyor track 3. In order to prevent the objects A from moving sideways in an uncontrollable fashion, longitudinal rails 5, € are present to either side of the track 3 and the track body 2; in Figures 2a, 2b and 3a, 3b, the rails of the track sections la, lb are designated as 5a, 6a, 5b, 6b. The mutual distance d between the rails 5, 6 is adjustable in line with the size of the objects 4, and in the area where the track sections la, lb meet, the ra ls 5, 6 have been given radii of curvature adapted to the distance d.

The rails 5, 6 are operatively connected to the track body 2 in at least two points situated close to the ends of each track section la, lb. In accordance with the invention, this operative connection comprises at each of the aforementioned points a shaft 7 rotatably mounted in the track body 2 and across it, which shaft has a thread 7a, 7b in its areas projecting beyond the track body 2, onto which thread a bracket 8, 9 supporting the respective rail is threaded. The threads 7a, 7b run in opposite directions to one another, so that when the shaft 7 is caused to rotate in one direction of rotation, the brackets 8, 9, and with them the rails 5, 6, are caused to approach one another, whilst the opposite

direction of rotation causes the brackets 8, 9 to move apart. In order to achieve parallel movement of the rails 5, 6, the shafts 7 are mechanically linked to and synchronized with one another both along a section la, lb of the track and along the entire transport track 1, for example by means of sprockets 10, 11 arranged on the shafts 7 and chains 10a, 11a running over the sprockets 10, 11. One of the shafts 7 is attached to a driving device, which driving device is a crank 12 in the embodiment illustrated in Fig. 1, although it is clear that a stepping motor, for example, may be used as the aforementioned driving device in an automatic system.

As already mentioned by way of introduction, it is important for the distance d between the rai s 5, 6 also to be maintained in the area where the track sections la, lb meet, irrespective of the size of the angle between the track sections la, lb. for this purpose, the ends of the rails 5, 6; 5a, 6a; 5b, 6b are executed in accordance with the invention with elements 13a, 13b, 14a, 14b, which interact in pairs and are shaped in such a way that the combination of the elements 13a, 13b forming an outer curve on one side and the elements 14a, 14b forming an inner curve on the other side produces arcs of circles having a mutual distance d identical with the mutual distance between the rail curves 13, 14, irrespective of the angle between the track sections la, lb. The elements also interact so as to ensure that the rails 5, 6 have radii of curvature adapted to the distance d.

The pairs of elements 13a, 13b and 14a, 14b are so arranged that they partially overlap one another, and so that an object may pass first along the delimiting surface 13al and Hal of one element 13a and 14a facing towards the object A, and then along the corresponding delimiting surfaces 13bl and 14bl of the second element 13b and 14b, in conjunction with which the delimiting surfaces 13al, 13bl together describe the arc of a circle forming the outer curve, and the delimiting surfaces 14al, 14bl form the arc of a circle which describes the inner curve. The arc angle of the circle arcs is approximately the same as the angle between the sections of the track.

In the embodiment of the arrangement in accordance with the invention

illustrated in Figures 3a, 3b, the track sections form an angle of 180 ^' with one another. Here the elements 14a, 14b forming the inner curve interact with a third element 15 securely arranged on the track body, the delimiting surface ISa of which, facing inwards towards the conveyor track 1, is so arranged, especially at small values for the distance d, as to form a bridge between the delimiting surfaces 14al and 14b1.