GB2102365A - Endless-track conveyor - Google Patents

Abstract

An endless-track conveyor has its conveying surface carried by two endless chain drives which, in use, travel in unison and are spaced laterally apart by a substantially unvarying amount along their common run. The conveying surface comprises a succession of spaced bars spanning the gap between the chain drives. The chains are roller chains, and each end region of each bar is fastened to an adjacent link of one of the chains by a resiliently deformable nylon insert (34) which projects from the underside of the bar into the gap defined between successive rollers of the chain, between the side plates (37) of the link, and ends in a portion (34a) which is larger than the narrowest part of said gap. <IMAGE>

Description

SPECIFICATION Endless-track conveyor The invention relates to endless-track conveyors.

The term "endless-track conveyor" is used in this specification to denote a conveyor whose conveying surface runs from one rotary driving element to another and is carried around each such driving element so that the conveying surface has a delivery run and a return run as it travels from one driving element to the other and back again.

In its broadest aspect the invention is embodied in an endless-track conveyor whose conveying surface is carried by two endless chain drives which, in use, travel in unison and which are spaced laterally apart by a substantially unvarying amount along their common run; the conveying surface comprising a succession of bars, each bar spanning the substantially unvarying lateral gap between the chain drives, and each bar being spaced along the run of the conveyor from the next bar by an amount which is so chosen as to cause articles, delivered to the conveyor, to lodge between and be carried along by adjacent bars without falling through the longitudinal gap between said bars; the chains of the chain drives being roller chains; and each end region of each bar being fastened to an adjacent link of one oF the chains by a fastening means which projects from the underside of the bar into the gap defined between successive rollers of the chain, passes through the narrowest part of said gap, and then ends in a portion which is larger than said narrowest part of said gap.

One conveyor embodying the invention is shown, by way of example only, in the accompanying drawings. It will be described with reference to those drawings. It has been developed specifically for conveying wrapped elongate cylindrical rolls of sweets to the stacking station of a high-speed wrapping and packaging machines. The invention is particularly applicable to machinery of this kind.

In the drawings: Figures 1 A and 1 B show respectively the rollaccepting and roll-discharging ends of the conveyor when viewed from above; Figures 2A and 2B show respectively the rollaccepting and roll-discharging ends of the conveyor when viewed from the side; and Figures 3A to 3C show in greater detail the means by which each end of each bar of the conveying surface is fastened to an adjacent link of the conveyor drive chain.

Figures 1A, 1 B, 2A and 2B are all drawn to the same scale. Figures 3A and 3B are enlarged in scale. Figure 3C is larger still.

The conveyor illustrated forms part of a larger machine whose overall purpose is to wrap a number of annular sweets into a circularcylindrical roll, deliver a succession of such wrapped rolls to a stacking station via the conveyor, form a succession of stacks of rolls, and box the stacks for subsequent dispatch. All these operations are carried out automatically by the machine.

The wrapping, roll-stacking and boxing operations of the machine do not form part of the present invention, and only the conveying part of the machine is illustrated in any detail in the drawings. Briefly, wrapped cylindrical rolls are delivered to the roll-accepting end of the conveyor in a direction indicated by the arrow A. They arrive in a continual flow. They reach the roll-accepting, or "infeed", end of the conveyor one behind another, in parallel but not co-axial alignment, and are indicated by the reference R in Figures 1 B, 2A and 2B. They are carried by the conveyor to the stacking station of the machine.

At the stacking station, indicated in Figures 1 B and 2B by the reference S, a desired number of rolls R is counted off the incoming flow, and the conveyor (and hence the flow) is temporarily stopped. The counted-off row of rolls is then elevated, and held in an elevated position, to form the top row of an eventual stack. The incoming flow of rolls R is started again, by starting the conveyor, a corresponding number is again counted off, the flow stops, and the second row of rolls is elevated so that it displaces the first row upwards and assumes the position previously occupied by the first row. These successive countings-off, stopping the flow, elevating the counted-off rolls, and starting the flow again, are repeated until a stack of desired height is attained.

The stack is then boxed. The stack rows of rolls may be stacked roll-on-roll, or may be nested, by the stacking means.

The conventional way of conveying the rolls from the infeed end of the conveying mechanism to the stacking station S is to use a so-called "walking beam" mechanism, in which two pairs of bars oscillate one within another; each pair of bars oscillating 1 BOC out of phase with the other; and the bars of one pair being formed along their upper surfaces with a succession of recesses.

These recesses pick up the rolls in succession at the infeed to the conveying mechanism.

The walking beam mechanism works well, but it has its drawbacks. One of these drawbacks is a tendency not to make a clean pick-up of each roll from the incoming flow of wrapped rolls. The conveyor illustrated and now to be described gives a cleaner and more reliable pick-up.

The conveyor shown is an endless-track conveyor whose conveying surface is defined by a series of elongate metal bars carried by two endless chain drives. The bars referenced 11 span the substantially unvarying lateral gap between the chains 12 of the drives. Each bar 11 is elongate and linear. When viewed from the side, as in Figures 2A and 2B, it has the cross section of an equilateral triangle whose apex is machined fiat. Each bar is spaced along the run of the conveyor from the next bar by an amount which is wide enough for one of the rolls R to lodge, as shown, between adjacent bars without falling through the gap between successive bars.

The chains 12 of the chain drives are roller chains. In use, with the conveyor operating, the chains travel in unison, i.e. they travel at the same speed as one another and the links of one chain travel alongside the links of the other chain so that the bars 11, when viewed from above, are carried along the run of the conveyor and maintained at right angles to the lines of travel of the two chains 12. As shown, the drive is transmitted to the rolldischarging end of the conveyor. A flexible toothed belt 1 3 connects the main drive sprocket 14 with a secondary sprocket 1 5. Another sprocket 1 6, carried on the same lay shaft as the sprocket 15, is iinked by a chain 17 to a further sprocket 1 8.

Another sprocket 19, carried on the same lay shaft as the sprocket 18, drives a roller chain 21 which itself drives a sprocket 22. The sprocket 22 is keyed to a shaft 23 which is channeled in the main frame 24 of the conveyor and which carries the two identical spaced-apart sprockets 25, 26 around which the chains 12 of the conveyor travel at the roll-discharging end of the conveyor.

A tensioning sprocket 18A takes up the slack in the return run of the roller chain 17, and a stop clutch 27 is carried by the lay shaft carrying the sprockets 18 and 1 9.

The sprockets 28, 29 at the roll-infeed end of the conveyor are rotated by the driven chains 1 2.

They are themselves keyed to a common shaft 31 which is rotatably journalled in blocks 32 fixed to the main frame 24 of the conveyor. Means for adjusting the longitudinal spacing between the two sets of sprockets 25, 26 and 28, 29 are illustrated in the drawings, referenced 33, but need not be described in detail.

A hard nylon insert projects from the underside of each end region of each bar 11. These inserts are best shown in Figures 3A, 3B and 3C. They are referenced 34. They are secured to the underside of their associated bar 11 by countersunk-headed screws 35 which pass through clearance bores drilled and countersunk down through the end regions of the bar 11 and which then enter bores drilled and tapped in the nylon inserts 34. The screws 35 may be screwed tight down against the bars 11, or instead a certain amount of play may be left between bar 11 and insert 34 to accommodate the inevitable very slight misalignment caused by backlash between the links of the chains 12. Each nylon insert 34 projects from the underside of its bar 11 into the gap defined between successive rollers 36 of each complete link of the chains 12.

As Figure 3C shows particularly clearly, the inserts 34 are so sized and shaped that they pass through the narrowest part of the gap between successive rollers 36 and then end in a portion 34a which is larger than that narrowest part of said gap. The longitudinally opposite surfaces 34B of each insert 34 are curved so as to embrace the facing curved surfaces of the rollers 36. The laterally opposite surfaces 34C of the insert are flat, and parallel, and are spaced apart so as to fit between the side plates 37 of the link. The insert is sufficiently deformable for the enlarged portion 34A to be force-fitted, from above, into and through the narrowest part of the longitudinal gap between successive rollers of the link, without having to take the link apart.It is also sufficiently resilient for the enlarged portion 34A to resume its enlarged shape once the insert has been so forcefitted into the link. The head portion 34D of the insert sits on top of, and bears against, the sideplates 37 of the link, whilst the enlarged tail portion 34A effectively presents the insert 34 from falling out from between the rollers of the link as the insert travels upside-down on the return run of the conveyor.

In use, a succession of wrapped cylindrical rolls arrives at the conveyor infeed, as shown in Figure 2A, along a delivery plate 38 and between laterally spaced-apart side guides (not shown).

The conveyor chains 1 2 travel from left to right when viewed as in the drawings. Each adjacent pair of bars 11 picks up one of the rolls R, as shown in Figure 2A, and carries it along the run of the conveyor to the stacking station S as shown in Figures 1 B and 2B.

The first roll to be picked up by bars 11 and leave the infeed end of the conveyor activates a proximity switch (not shown). This starts a "count" sequence in the programmable logic controller governing the operation of the entire machine. When a predetermined number of rolls has been picked up and carried away from the infeed end of the conveyor, and has reached and been discharged into the stacking station S, the conveyor is automatically stopped. The elevating, stacking, re-starting of the conveyor, and counting-off the next row of rolls R, then proceed to constitute a second cycle of operation of the conveying mechanism. The cycle is repeated to build up the desired stack height, all as previously outlined.

Side guides 39, 41 are spaced apart laterally across the conveyor by an amount which is just slightly greater than the overall length of each roll R to be carried by the conveyor. They run parallel to the lines of travel of the conveyor chains 12. As Figure 1 B shows, they keep successive rolls R in lateral alignment with one another until they are delivered to 42, 43, the similar side guides forming part of the stacking station of the machine.

The conveyor described and illustrated gives a clean pick-up of rolls R from the infeed. It is mechanically simple and robust, and its nylon inserts 34 do not need lubrication, nor do they interfere unduly with the operation of the chains 12. The clean pick-up and constant spacing of the rolls R makes it easy for an accurate "count" to be made and repeated, and individual parts of the mechanism can easily be serviced without the whole machine having to be stopped for long periods.

The sprockets 25, 26 and 28, 29, which support the conveying chains 12, each have every alternate tooth removed. The inserts 34 can then project into the gaps created by removing those teeth. The remaining teeth on the sprockets engage the chain rollers between each complete link of the chain, to transmit the conveying drive.

Claims (7)

1. An endless-track conveyor whose conveying surface is carried by two endless chain drives which, in use, travel in unison and which are spaced laterally apart by a substantially unvarying amount along their common run; the conveying surface comprising a succession of bars; each bar spanning the substantially unvarying lateral gap between the chain drives, and each bar being spaced along the run of the conveyor from the next bar by an amount which is so chosen as to cause articles, delivered to the conveyor, to lodge between and be carried along by adjacent bars without falling through the longitudinal gap between said bars; the chains of the chain drives being roller chains; and each end region of each bar being fastened to an adjacent link of one of the chains by a fastening means which projects from the underside of the bar into the gap defined between successive rollers of the chain, passes through the narrowest part of said gap, and then ends in a portion which is larger than said narrowest part of said gap.

2. A conveyor according to Claim 1 and in which each bar has the cross section of an equilateral triangle.

3. A conveyor according to Claim 2 and in which the top apex of the triangular bar is machined flat.

4. A conveyor according to any of the preceding Claims and in which the fastening means are of synthetic plastics material.

5. A conveyor according to Claim 4 and in which the fastening means are sufficiently resiliently deformable, and are so sized and shaped, as to be able to be force-fitted into and through the narrowest part of the longitudinal gap between successive rollers of the associated chain link, without having to take the link apart.

6. A conveyor according to any of the preceding Claims and in which each bar is secured to its associated fastening means in a manner which allows a certain amount of play between bar and fastening means to accommodate any misalignment between the conveyor chains.

7. A conveyor incorporating a succession of bars and associated fastening means substantially as described herein with reference to and as illustrated in the accompanying drawings.