IE52410B1 - Transfer conveying assembly - Google Patents

Abstract

A transfer conveying assembly 10 (Fig. 1) having a first section 12 and a telescopic second section 13 pivotally connected to the first section at 15. Together the two sections carry a belt assembly 17 for transferring produce from the discharge end of a bulk conveyor 19 to a point at or near the surface (not shown) on to which the produce is to be unloaded.

Description

TRANSFER CONVEYING ASSEMBLY The present invention relates to a transfer conveying assembly, e.g. for use in filling bulk containers with potatoes or other agricultural produce.

Each year many thousands of tonnes of potatoes and to a 05 lesser extent carrots and other agricultural produce are loaded into hulk lorries or other high-sided containers.

Usually the produce will be delivered into the container from the end of a bulk conveyor Aich obviously must be high enough to clear the sides of the container. Typically, with a conventional high-sided container, the produce will drop from fOUl” feet (122 cm) up to eight feet (244 cm) or ten feet (305 cm) from the end of the bulk conveyor during the initial stages of loading causing it to bruise or split as it impacts against the floor of the container or against other produce or stones, etc. already present there. During the later stages of loading, the presence of produce already in the container will mean that newly arriving produce will have a smaller distance to fall through but damage will still occur, though to a lesser extent, due to impact and rolling, etc.

Past attempts to reduce the amount of free fall of the produce into the container include the fitting to the discharge end of the bulk conveyor of a downwardly-directed transfer chute of zig-zag pattern or having fall-arresting flaps. However, in both cases, the chute induces rolling and material impacts which could cause skinning of the produce especially in the presence of stones or hard clods.

An object of the present invention is to provide a means for significantly reducing the risk of damage to agricultural produce by impact, etc. during unloading of the produce into a container.

A transfer conveying assembly according to the present 30 invention comprises a first section for mounting at the discharge end of a bulk conveyor, a telescopic second section pivotally connected with the first section, and at least one endless flighted transfer conveyor jointly supported from the distal end of the second section and from a compensating device mounted on the first section, said compensating device being movable along the first section so that the path length of the transfer conveyor is maintained substantially constant despite changes in the overall length of the second section and in the inclination of this section relative to the first section.

The term telescopic in this context should be interpreted broadly as covering any second section consisting of different parts which move relative to one another to alter the effective length of that section. In practice, the path followed by each point of the transfer conveyor will be defined by various parts of the assembly around which the transfer conveyor passes and the term path length in the above context is to be interpreted as meaning the sum of the distances between adjacent ones of these path-defining parts. The term flighted conveyor should be widely interpreted as referring to any transfer conveyor having surface projections and/or depressions on its load-supporting surface designed to prevent or discourage significant movement of the supported load relative to that surface.

The value of having the path length substantially constant is that it allows the second section of the assembly to be continuously repositioned throughout the loading operation so that the transfer conveyor will at all times be able to discharge produce received from the bulk conveyor straight onto the container floor (or on to produce already in the container) with the minimum of free drop. Had the path length of the transfer conveyor been dependent on the extension of the second section and/or the relative inclinations of the two section, this would have imposed undesirable operating restrictions on the assembly if unacceptable slackness or tension in the transfer belt were to be avoided.

It is an advantage of the assembly of the present invention over systems using the roll-inducing transfer chutes discussed earlier, that the produce can now be carried passively to the point of release, i.e. with substantially no relative movement between the produce and the endless transfer conveyor.

Conveniently, the length of the second section and the position of the compensation device on the first section are both controlled from a single ram arrangement operative, as desired, either, on the one hand, to move the compensating device and permit the corresponding extension or retraction of the second section required to keep the path length of the transfer conveyor substantially constant or, on the other hand, to produce an extension or retraction of the second section and permit the corresponding movement of the compensating device required to keep the path length of the transfer conveyor substantially constant.

It will be understood that the transfer conveying assembly of the present ivention may take the form of an attachment for existing bulk conveyors, or it could he fabricated integrally with such a conveyor. Because the assembly is necessarily mounted at the distal end of the bulk conveyor, it is desirably of relatively lightweight construction. A heavy construction would impose a large overturning moment on the bulk conveyor and would bring about a need for heavy counterbalancing and strengthening of the bulk conveyor frame.

An embodiment of the invention will now he described, by way of example only, with reference to the accompanying drawings in which :Figure 1 is a general view of a transfer conveying assembly according to the present invention shown mounted on the discharge end of the conventional bulk conveyor; Figure 2 shows the assembly fully extended; Figure 3 shows the assembly fully retracted; Figure 4 is a side view showing a control ram and cables for use in the assembly; Figure 5 is a partially diagrammatic plan view of the cable control system; and Figure 6 is a diagrammatic representation of a height control system for use with the assembly of Figures 1 to 3.

Thus referring first to Figure 1, a transfer conveying assembly in accordance with the present invention is shown in the form of an attachment device 10 having a first section 12 and a telescopic second section 13 pivotally connected to the first section at 15. Together the two sections carry a belt assembly 17 for transferring produce from the discharge end of a bulk conveyor 19 to a point at or near the surface (not shown) on to which the produce is to be unloaded.

The first section 12 of the device comprises frame members 21 of channel-section profile which are bolted to the side plates of bulk conveyor 19 by brackets 22 on each side of the conveyor.

The second section 13 comprises a base part 24 and an extension part 25 movable relative to base part 24 to provide the desired telescopic effect.

In more detail, extension part 25 comprises a canopy 27 mounted on a frame 28 which is in turn supported on rollers 29 (Figure 2) running in the channel sections of a second pair of frame-members 31. These second frame-members, which belong to base part 24, are pivotally attached to the first members 21 at the pivot 15 and they carry a second canopy 33 of aluminium or other light-weight material over which the first canopy 27 slides when section 13 is expanded or retracted.

The inclination of second section 13 relative to first section 12 is controlled by a hydraulic ram 35 connected to the two sections by stirrup brackets 37, 38 respectively. In operation, this ram is effective to move the second section to any described position between a first position (shown in Figure 1) in which it lies at approximately 90° to the first section and a second position (not illustrated) in which the angle between the · two sections has been increased to such an extent that they are almost in a straight line with one another.

The transfer conveyor of the illustrated device is of course provided by the flighted belt assembly 17 in which the flights 40 are bolted to the side lugs (not shown) of a pair of side chains of which only one chain (42) is visible in the drawing. The load-bearing part of the assembly is provided by a plain belt 44 sandwiched between the flights 40 and the chain lugs. In a variation (not shorn) the flights 40 are moulded to belt 44 and it is this latter which is attached to the side chains.

The upper runs of the side chains 42 pass over a pair of driven sprockets 45 (Figure 3) having a shaft 46 which is substantially unaffected by any change in the relative inclinations of the two sections. The drive (not shown) to these sprockets is by a vee-belt 47 (Figure 1) taken from a pulley 49 on the head roller shaft 50 of the bulk conveyor 19 to a pulley 51 on the sprocket shaft 46.

The lower runs of the side chains negotiate the angle at the pivot point between the two sections by passing over two pairs of sprockets 52, 52' (Figure 3). These are spaced sufficiently apart to minimise any likelihood of the belt flights clashing, for example When section 13 is inclined at 90° or so relative to c the bulk conveyor.

At the lower end of the belt assembly, the chains 42 pass around another pair of sprockets mounted on the distal end of section 13. Only one of these sprockets (sprocket 54) is visible in Figure 3. At the other end of the assembly the chains pass over a pair of sprockets carried by a carriage 60 which is mounted for limited longitudinal movement along frame-members 21 beneath the bulk conveyor 19. Once again only one of these sprockets (sprocket 57) is visible. The lower runs of the chains between the end sprockets 54 and 57 and the central sprockets 45, 52 are supported by wooden slides 62, 63 attached to the first and second sections respectively.

The extensions of section 13 and the position of carriage 60 are controlled through cables 65, 66 from a single ram arrangement 68 in such a way that movement of the carriage 60 at one end of the belt assembly closely copies that of extension part 25 at the other end of the assembly. In this way, the path length of the belt assembly is maintained substantially constant despite changes in the overall length of the second section.

The double-acting ram arrangement 68 and the associated part of the cable control system 65, 66 are shown in detail in Figure 4 where reference numeral 70 indicates the ram cylinder secured to the bulk conveyor housing by bracket 72 and reference numeral 75 indicates a free-running pulley secured further up the conveyor by a second bracket 77.

The piston rod 79 of the ram arrangement extends to the upper side of the ram cylinder 70 which has a bifurcated portion 81 extending from its base. The rod 79 terminates in a similar bifurcated portion 82. Portions 81, 82 carry pairs of free-running pulleys 84, 84', and 85, 85' respectively, one pulley (84', 85') of each pair of pulleys being masked by the other pulley of the pair (84, 85) in the side view of Figure 4.

An attachment lug 87 extending upwardly from portion 82 completes the arrangement.

The cable control system comprises a first cable 65 which for convenience is shown in black in Figure 4 and a second cable 66 which for convenience is shown in white. Figure 5 shows how the two cables are attached at their lower ends.

Referring first to Figure 4, the uppermost end of cable 65 is locked in lug 87 from which the cable passes in succession around pulleys 84, 85 and 84' before passing to the lower end of the assembly. There (Figure 5) it is secured to the top end of extension part 25 after passing round redirection pulleys 89, 90 carried by the base part 24 and by the inter-section pivot 15 respectively.

The uppermost end of return cable 66 is secured to the end of ram portion 82 (Figure 4) and thereafter the cable passes in succession around pulleys 75 and 85' before passing to the lower end of the assembly (Figure 5) where it is secured to the upper end of carriage 60. Pulleys 92, 93 secured to the housing of bulk conveyor 19 are used to bring cable 66 to the same side of the bulk conveyor as cable 65.

For clarity, the various belt assembly pulleys and the associated cables 65, 66 have been omitted from the other Figures of the drawings.

In operation, the ram arrangement 68 is actuated by a control valve (not shown) to supply oil to either side of the ram piston and it should be clear from Figure 4 and the accompanying description that then the ram piston rod 79 is moved to the left (as viewed in that Figure) then the cable 65 will be pulled to the right by three times the amount of the ram movement resulting in a corresponding extension of part 25 (Figure 5). The forward movement of sprockets 54 with this part will bodily displace the transfer belt 44 by the same amount causing a similar movement of the carriage 60 at the other end of the belt. This latter movement is allowed in controlled fashion by the second cable 66 which is paid out to the left by the movement of the piston rod 79, this cable moving by exactly the same amount as cable 65 moves to the right namely three times the ram movement. Typically, the maximum extension of the telescopic section would be 1.37 metres.

When the piston rod 79 is moved to the right (as viewed in Figure 4), then the two cables 65, 66 will move in the opposite directions to those described, the carriage 60 being pulled by cable 66 to the right in this case and the extension part 25 being pulled into the base part 24 by the transfer belt 44 in a controlled fashion allowed by the simultaneous pay out of cable 65.

It will therefore be appreciated that by suitable operation of ram arrangement 68 and the pivot ram 35, the assembly can be so disposed as always to transfer produce from the discharge end of the bulk conveyor 19 direct to the empty floor of the container or to the upper surface of produce already in the container thereby minimising the risk of damage to the produce by bruising, etc.

Control of the extension and retraction of the telescopic section 13 may be either manually or desirably, but not essentially, by sensor ball 95 (Figures 1 to 3) connected to an automatic height control system of the sort available commercially, e.g. from Cranford Engineering of Knutsford, Cheshire.

Conveniently, in this latter case, a solenoid valve is present to control the operation of the ram arrangement 68 and an electronic control box is also included to cause the conveyor end automatically to advance and retract over a small distance in cyclic fashion as in the Cranford height control system referred to above.

One example of such a system shown in Figure 6 includes a solenoid spool valve 99 controlling the hydraulic power supply 100, 101 to the ram 70. The valve 99 is operated from a control box 102 powered from a direct current electric supply 103 and the system is completed by an air switch 104 mounted on the side wall of the conveyor 19 and connected between the sensor 95 and the valve 99. Reference numeral 105 indicates an air bleed button for the switch 104.

The control box 102 referred to above has an UP button 106, a DOWN button 107 and an AUTO button 108. There is also a variable delay control knob 109.

When the AUTO button 108 is pressed, e.g. to load potatoes into a lorry (not shown), the valve 99 is energised and the double acting hydraulic ram 70 extends the telescopic second part 25 of the assembly until the sensor ball 95 touches the floor of the lorry or the bulk heap of potatoes, as the case may be. The sensor ball 95 then becomes slightly depressed and air leaving the ball via an air tube 110 closes the pressureresponsive air switch 104 which in turn triggers an automatic control in the control box 102. This latter causes the valve 99 to operate in such a way as to retract conveyor part 25 for a variable time delay (set by control knob 109) typically of about 1.5 seconds. After the delay, the telescopic part 25 is allowed to extend again until the ball 95 once more touches the heap of potatoes now building up in the lorry whereupon the control box 102 operates to return valve 99 to its original position, thereby causing a second temporary retraction of part 25 and sensor ball 95. When the lorry has been loaded to a predetermined depth, e.g. 1.2 to 1.5 metres, then the operator will activate an appropriate stop button to stop the conveyor.

The UP and DOWN buttons 106, 107 In control box 102 allow manual over-riding of the AUTO function referred to above and a lift adjuster 115 on valve 99 enables the rate of extension and retraction of part 25 to be varied. Reference numeral 117 indicates a manual over-ride button for the valve.

An additional optional feature is to have a command device for the lifting ram (not shown) of bulk conveyor 19 which is operative to expand the lifting ram when device 10 is fully retracted but a greater depth of material in the container is required.

Another optional feature is to have a remote manual control consisting of an electric cable and pendant hand switch unit 112, or remote control unit, to enable an operator stationed at the bulk container to command the lifting ram of the bulk conveyor to operate vhen the device 10 is fully retracted. The above means could also be used to control the functions of extending, contracting, and luffing the device 10 and for automatic operation of the height control system.

The tension in the conveyor belt is maintained irrespective of any wear in the chains 42 by means of turnbuckles (not shown) at the attachment points of cables 65, 66 to carriage 60 and attachment lug 87. Alternatively, if desired, the cables 65, 66 in the illustrated embodiment may be replaced by hydraulic rams though this leads to a heavier machine.

Claims (4)

1. A transfer conveying assembly comprising a first section for mounting at the discharge end of a bulk conveyor, a telescopic second section pivotally connected with the first section, and at least one endless flighted transfer conveyor jointly supported from the distal end of the second section and from a compensating device mounted on the first section, said compensating device being movable along the first section so that the path length of the transfer conveyor is maintained substantially constant despite changes in the overall length of the second section and in the inclination of this section relative to the first section.

2. An assembly as claimed in Claim 1 in which the length of the second section and the position of the compensating device on the first section are both controlled from a single ram arrangement operative, as desired, either, on the one hand, to move the compensating device and permit the corresponding extension or retraction of the second section required to keep the path length of the transfer conveyor substantially constant, or, on the other hand, to produce an extension or retraction of the second section and permit the corresponding movement of the compensating device required to keep the path length of the transfer conveyor substantially constant.

3. A transfer conveying assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

4. A bulk conveyor incorporating a transfer conveying assembly as claimed in any of Claims 1 to 3.