GB2184083A - Conveyor - Google Patents

Abstract

A conveyor 1 comprising a plurality of laterally alternating first and second beams 2, 3 extending longitudinally in the required conveying direction, each beam 2, 3 having a toothed surface 7 for conveying and/or accumulating products 5, each tooth 8 being at regular pitch and having asymmetrical tooth flanks 9, 11, with the first and/or the second beams 2, 3 capable of being elevated and lowered, in a level or a rocking motion, with respect to one another, and the teeth 8 of the first beams 2 being laterally staggered with respect to the teeth 8 of the second beams 3 to cause longitudinal movement of products 5 along the beams until they are accumulated via an end stop 14. <IMAGE>

Description

SPECIFICATION Conveyor This invention relates to a conveyor, particularly though not exclusively for the conveying of products, whether finished or semi-finished, having a circular external periphery, such as cylinders, rods, tubes, barrels, cans; of a variety of different materials such as metal, carbon, plastics, ceramics, refractories etc.

A common additional requirement, beyond the primary, conveying function of the conveyor is a product accumulating capacity, for in many manufacturing operations, the rate of loading of products onto the conveyor e.g.

when one manufacturing stage has been completed, for transport to the unloading end of the conveyor, is out of phase with the rate of unloading of those products for subsequent processing.

At least two prior art techniques have been proposed to meet this dual role. One technique, usable where the conveyor is already partially loaded, consists of depositing a product(s) part-way along the conveyor in accordance with the position along the conveyor of the last deposited product, but this technique requires positional sensing equipment to determine the position of the last deposited product, as well as means to lift, transport, and deposit the product(s) on the conveyor at the "sensed" position. The requirement for such ancillary equipment results in increased complexity as well as installation and maintenance costs.The other technique consists of inclining a rolling bed type conveyor from an elevated, loading end to a depressed, unloading end so that products may roll down the conveyor and "sense" the previously loaded product by striking that product, but the nature of the material of some products, such as carbon electrodes, frequently results in product damage, and the required conveyor length and hence the energy that a product acquires in a relatively long downhill run renders this technique unsuitable in many applications.

According to the present invention, there is provided a conveyor comprising a plurality of laterally alternating first and second beams extending longitudinally in the required conveying direction, each beam having a toothed, product receiving surface on which products to be conveyed and/or accumulated are adapted to seat, each tooth being at regular pitch and having asymetical tooth flanks, being a shorter length, leading flank constituting a product stop surface separated by a tooth tip from a longer length trailing flank constituting a product rolling surface, with the first and/or the second beams capable of being elevated and lowered, totally or in part, with respect to one another, and the teeth of the first beams being so laterally staggered with respect to the teeth of the second beams that a product supported against stop surfaces of the first beams is, upon repeated elevating and lowering of the first beams with respect to the second beams, or conversely of the second beams with respect to the first beams, repeatedly transferred from static location against stop surfaces of the first or second beams to rolling surfaces of the second or first beams, to roll down those surfaces until the product encounters the stop surface of the next tooth of the beam on which it is seated, thus to be conveyed in step wise manner along the roller surfaces and hence along the conveyor and/or accumulated progressively along the conveyor.

The invention thus provides a conveyor in which the requirement of prior art proposals for the expense, complexity, and maintenance of product sensing and lifting/lowering equipment is avoided as is the disadvantageous energy build up encountered with the use of downhill conveyors.

The conveyor in accordance with the invention would normally comprise at least two first beams and at least two second beams, but the numbers of beams depend on the width required for the conveyor, which in turn is dictated by the length of products to be conveyed and/or accumulated, as well as the characteristics of the material of the products-such as the toughness and rigidity of a steel pipe compared with the relative fragility of a carbon electrode; ceramic, refractory, or plastics rod or tube, particularly if such products are at elevated temperatures or in a green state.

However, there is in principle no limit to the numbers of first and second beams that may be employed in a conveyor of the invention and twenty first beams may alternate with twenty second beams for instance.

It is desirable, of course, that the unloading end of the conveyor is provided with a releasable or removable stop means which remains inactive whilever unloading is required, but which is activated when no unloading, but merely accumulation, is required.

Although both the first and the second beams could be capable of elevation with respect to one another, it is sufficient if only the first (or the second) beams are of fixed position, and the second (or the first) beams are capable of elevation, in which case the first beams are static beams and the second beams are lifting/lowering beams, serving to lift products, during conveying and/or accumulating, from stop flanks of teeth of the first beams onto rolling surfaces of teeth of the second beams, to roll along those surfaces and to abut the next encountered stop surfaces, with lowering of the second beams redepositing the products onto the next downstream rolling surfaces of the first beams, because of the advance of the product whilst on the second beams.

Any suitable mechanism may be employed for lifting the second beams, and in many instances, to lifting of the second beams, by displacing their leading and trailing ends by the same or differing vertical distance, presents no difficulties. It will be appreciated however, that when the conveyor is fully loaded, or substantially so, then the forces required to effect lifting may become excessive, particularly if relatively heavy products such as steel rods or bars are involved, and hence in accordance with a further proposal of the invention, only selective parts of the second beams are lifted, by a rocking action, resulting in the product individually being lifted and thus permitted to advance, thereby minimising the kinetic energy imparted to the product as it rolls down a rolling surface, which energy needs to be absorbed by the conveyor.Thus, rocking upwardly the ends of the second beams adjacent the unloading end of the conveyor results only in a product(s) located adjacent the unloading end of those beams being elevated and hence advanced.

With the space created by such advance, the subsequent rocking upwardly of the ends of the second beams adjacent the loading end of the conveyor results in the products located towards the loading ends of the second beams being individually elevated and hence advanced.

The lifting/lowering cycle of the second beams may be operated continuaily or intermittantly, depending on the rates of loading and unloading of products to and from the conveyor.

The invention will now be described in greater detail, by way of examples, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic side elevation of a first embodiment of conveyor in accordance with the invention in a first position; Figure 2 corresponds to Figure 1 but shows a second position; Figure 3 corresponds to Figure 1 but shows a third position; Figure 4 also corresponds to 1 to 3 but shows the accumulation of products; Figure 5 is a diagrammatic side elevation of a second embodiment of conveyor in accordance with the invention in a first position; Figure 6 corresponds to Figure 5 but shows a second position; Figure 7 corresponds to Figure 5 but shows a third position; Figure 8 corresponds to Figure 5 but shows a fourth position;; In the drawings, a conveyor comprises a plurality of laterally alternating, first arid second beams, 2 and 3 respectively extending longitudinally in the required conveying direction, which is indicated by arrow 9, for the conveying and/or accumulation of a product 5 having a circular external periphery 6, the first beam 2 being in fixed position and constituting a static beam, and the second beam 3 being displaceable with respect to the first beam, and constituting a lifting beam. Only one beam 2 and one beam 3 are visible, the number of beams making up the conveyor 1 being dependent on the axial lengths of the products 5 to be handled by the conveyor 1.

Each beam 2 3 has a toothed, product receiving surface 7, with each tooth 8 thereof being at regular pitch and having asymetrical tooth flanks, being a shorter length, leading flank 9 constituting a product stop surface and separated by a tooth tip 10 from a longer length, trailing flank 11 constituting a product rolling surface, with the teeth 8 of the beam 2 being laterally staggered with respect to the teeth 8 of the beam 3, whilst the conveyor 1 has a loading end 12 onto which products 5 are loaded, by any convenient means, at a regular or intermittent rate, and a discharge end 13, the latter being provided with a removable stop mechanism 14, operation of which enables products to be discharged at a regular or intermittent rate, as required.

In operation, a product 5 to be conveyed and/or accumulated by the conveyor 1 is loaded onto the conveyor 1 at the loading end 12 by a rolling action, with the lifting beam 3 in its lower position as illustrated in Figure 1, until the product 5 strikes the leading flank/stop surface 9 of the first tooth 8 of the static beam 2. Thereafter, to progress the product 5 along the conveyor 1, the lifting beam 3 is raised so that the trailing flank/rolling surface 11 of the first tooth 8 of the lifting beam 3 lifts the product 5 from the leading flank/stop surface 9 of the first tooth 8 of the static beam 2, with the product advancing along the conveyor 1 from the position illustrated in Figure 1, to the position illustrated in Figure 2, by rolling along the trailing flank/rolling surface 11 of the first tooth 8 of the lifting beam 3.To advance the product 5 further along the conveyor 1, the lifting beam 3 is lowered from the position shown in Figure 2 to the position shown in Figure 3, during the course of which lowering the product 5 is deposited onto the trailing flank/rolling surface 11 of the first tooth 8 of the static beam 2, the product 5 rolling along such surface until its progress is halted by abutting the leading flank/stop surface 9 of the second tooth 8 of the static beam 2. This process of lifting and lowering the lifting beam 3 to cause progressive, step-wise movement of the product 5 along the conveyor 1 is repeated until the product 5 strikes the stop mechanism 14, with removal or withdrawal of the stop mechanism 14 enabling products 5 to be discharged from the conveyor 1, as and when required. As indicated in Figures 1 to 3, the lifting beams 3 are lifted in toto, and consequently is the product 5, or are all the products 5, that is or are on the conveyor 1, and this system is satisfactory provided the pro ducts 5 are of reasonable weight capable of being lifted by a reasonably powered and hence economical lifting means e.g. a plurality of hydraulic rams, and hence the embodiment of Figures 1 to 3 is suitable where the products 5 are for instance carbon electrodes, or ceramic, refractory or plastics rods or tubes.

Figure 4 indicates the product accumulation possibilities of the conveyor 1, with the stop mechanism 14 remaining in position and a succession of products 5 being placed on the loading end 12 of the conveyor 1 to be progressed long the conveyor 1 and hence accumulated by the conveyor 1, for subsequent removal, by retraction of the stop mechanism 14, as and when required.

In the embodiment of Figures 5 to 8, the products 5 are assumed to be steel rods or tubes, and hence of substantial weight, and accordingly the lifting beams 3 and with them the products 5 are not lifted in toto, as described with reference to Figures 1 to 3, but on the contrary are lifted by a rocking action, whereby selective parts only of the lifting beams 3 are lifted at any one time and hence only a few products 5. Consequently, the lifting mechanism may have an economical lifting capacity. Lifting by the rocking action can readily be effected by selective operation of hydraulic rams located at or towards opposite ends of the lifting beams 3.Thus, a first hydraulic ram 1 5 may be located towards the discharge end 13 of the conveyor 1, to produce a lifting action as indicated by arrow 16 in Figure 5, while a second hydraulic ram 18 may be located towards the loading end 12 of the conveyor 1, to produce a lifting action as indicated by arrow 18 in Figure 6, after which the lifting beams 3 have been fully lifted.

Thereafter, the ram 1 5 is retracted to produce a lowering action as indicated by arrow 19 in Figure 8, after which the ram 18 is retracted, to produce a lowering action indicated by arrow 20, after which the lifting beams 3 have been fully lowered. During this rocking lifting/lowering action of the lifting beams 3, the products 5 either engage leading flanks/stop surfaces 9 of teeth 8, or alternatively roll along trailing flanks/rolling surfaces 11 of teeth 8, dependent upon their position along the conveyor 1 and the portion of the lifting beams 3 that is being lifting, or lowered, at any one time, to follow the same product advancing technique as described with reference to Figure 1.

Claims (8)

1. A conveyor comprising a plurality of laterally alternating first and second beams extending longitudinally in the required conveying direction, each beam having a toothed, product receiving surface on which products to be conveyed and/or accumulated are adapted to seat, each tooth being at regular pitch and having asymetical tooth flanks, being a shorter length, leading flank constituting a product stop surface separated by a tooth tip from a longer length trailing flank constituting a product rolling surface, with the first and/or the second beams capable of being elevated and lowered, totally or in part, with respect to one another, and the teeth of the first beams being so laterally staggered with respect to the teeth of the second beams that a product supported against stop surfaces of the first beams is, upon repeated elevating and lowering of the first beams with respect to the second beams, or conversely of the second beams with respect to the first beams, repeatedly transferred from static location against stop surfaces of the first or second beams to rolling surfaces of the second or first beams, to roll down those surfaces until the product encounters the stop surface of the next tooth of the beam on which it is seated, thus to be conveyed in step wise manner along the roller surfaces and hence along the conveyor and/or accumulated progressively along the conveyor.

2. A conveyor as claimed in Claim comprising at least two first beams and at least two second beams.

3. A conveyor as claimed in Claim 1 or Claim 2, wherein the unloading end of the conveyor is provided with a releasable or removable stop means which remains inactive whilever unloading is required, but which is activated when no unloading, but merely accumulation, is required.

4. A conveyor as claimed in any preceding Claim, wherein both the first and second beams are capable of elevation with respect to one another.

5. A conveyor as claimed in any one of Claims 1 to 3, wherein only the first (or the second) beams are of fixed position, and the second (or the first) beams are capable of elevation.

6. A conveyor as claimed in any preceding Claim wherein only selective parts of the second beams are lifted, by a rocking action, resulting in the product individually being lifted and thus permitted to advance.

7. A conveyor substantially as hereinbefore described with reference to Figures 1 to 4 of the accompanying drawings.

8. A conveyor substantially as hereinbefore described with reference to Figures 5 to 8 of the accompanying drawings.