GB2214153A

GB2214153A - Conveyor

Info

Publication number: GB2214153A
Application number: GB8901074A
Authority: GB
Inventors: Gerald Richard Oldham Pentith; Lewis Robert Barnes Bower
Original assignee: Fletcher Sutcliffe Wild Ltd
Current assignee: Fletcher Sutcliffe Wild Ltd
Priority date: 1988-01-23
Filing date: 1989-01-18
Publication date: 1989-08-31
Also published as: GB8801531D0; GB8901074D0

Abstract

A conveyor for e.g. coal comprises a conveying surface (11) with reciprocably movable, pivotally mounted flights (20) extending transversely over the surface and movable along the surface to convey material. The flights are pivotted by the material, on reverse movement along the surface, to positions (21) extending lengthwise of the surface. The flights extend inwardly from both opposite sides of the conveyor surface with those on one side alternating with those on the other side. The flights are driven in reverse much more quickly than in the operating direction by e.g. hydraulic rams, one at each end of a driving chain such that all the flights move together for part of the reciprocating cycle in the conveying direction. <IMAGE>

Description

CONVEYOR APPARATUS This invention relates to conveyor apparatus and especially such apparatus for use in working mineral faces, for example coal or other deposits.

Conveyor apparatus for use in working a mineral face is required to remove material excavated by a mineral excavating machine, for example a shearer or plough. One known conveyor commonly referred to as an armoured face conveyor comprises a series of so-called "pans" each about five feet in length. The pans are generally of trough-like configuration and connected to one another to provide a conveying channel. In each pan, a horizontal partition of deck plates is provided defining upper and lower decks. In such an armoured face conveyor, a conveyor chain runs on a conveying surface defined by the top of the deck plate, the upper deck being open to material being loaded. The return run of the chain is accommodated beneath the plate in the lower deck.The chains, whether single or double, are formed in a continuous loop tensioned by suitable means, for example external rams, the chains being wrapped around a driving sprocket at each end of the face being worked. The chain or chains must be sufficiently tensioned to avoid slack, since otherwise bunching and jamming could occur. If tension is too great, there is excessive wear of the chain links. Flights attached to the chains scrape material along the conveying surface to convey material from one end of the face towards an exit at the other.

From time to time the flights and the chains are heavily loaded, occasionally with heavy shock loading, and the connectors which join lengths of chain together, being of split construction, tend to be weaker than the remainder of the chain and prone to break.

FR-A-875706 discloses a different arrangement in which flights are pivotally mounted at spaced intervals along each pan at both opposite sides of the pan. The flights are mounted on rods which can be reciprocated lengthwise of the pans. Each flight is pivotally movable from a stowed position extending parallel to the sides of the pan to an operative position extending transversely across the conveying surface. Material is conveyed by the flights as the rods are moved in the conveying direction, with the flights in the operative position. On return of the rods, the flights move to the stowed position, so that reciprocation of the rods advances the material along the conveying surface.The flights are spring-urged to the stowed position and urged by cams to the operative position as the rods reach the end of the return stroke.

This arrangement avoids some of the problems of the continuous chain type conveyors, but the intermittent operation tends to be slow and substantial force is applied to the flights as they begin to move in the conveying direction, so that the are liable to break.

The present invention provides conveying apparatus comprising an elongate conveyor surface for supporting material to be conveyed and along which the material is moved, flights spaced along the conveyor surface, each flight being mounted for pivotal movement between a conveying position extending transversely of the conveyor surface and a reversing position extending generally longitudinally of the conveyor surface, drive means for causing said pivotal movement and for reciprocating each flight longitudinally of the conveyor, characterised in b control means controlling the reciprocation so that the reversing speed of the flights is substantially greater than the conveying speed.

Reference is made to DE-C-611D36. This document, which dates from 1935, has no connection either with conveyors, or with the mining field. The document discloses a raking system for use in separating tanks. The rakes are so mounted and controlled that one rake advances as another is retracted. This basic principle could not be applied to conveyors of the type with which the present invention is concerned without the application of substantial expertise. The drive system of this document is unsuited to conveyors. Reference is also made to DE-C666040 and DE-C-906917, all three of which documents hae been located b searching.

Reference is now made to the accompanying drawings, wherein Figure 1 is a plan view of part of a conveyor according to the invention: Figure 2 is a sectional view on the line A of Figure 1; Figure 3 is a sectional view on the line B--B of Figure 1, but showing a flight in its reversing position; Figure 4 is a sectional view on the line C--C of Figure 1; Figure 5 is a diagrammatic view of a part of the conveyor showing an additional drive unit; Figure 6 is a view similar to Figure 5, showing an alternative additional drive unit; Figure 7 is a circuit diagram showing operation of the main drive system; and Figure 8 is a diagram showing operational timing of the conveyor.

The conveyor shorn is made up of pans joined end to end to form a long conveyor to be laid alongside a mine face. Each pan comprises a base plate 10 and side members 17, the upper surface of the base plate between the members defining a conveying surface 11. Each side member supports a horizontal rail 1D, extending inwardly of the conveyor pan and having a trapping member 16 e.utendin8 downwardly at its inside end.

Flights 20, 21 are spaced along the pan estendin8 inwardly from both opposite sides of the pan. The flights at one side alternate with those at the opposite side and each flight is pivotally movable between a conveving position, as shown at the bottom of Figure 1, and a reversing position, as shown at the top of Figure 1. In the conveying position, each flight extends transversely across the conveying surface 11, e.g. over about 75% of the width of the surface. In the reversing position, each flight lies generally parallel to the length of the conveyor pan. In Figure 1, the lower flights 20 are moving towards the right in a conveying direction, moving mineral along the conveying surface, whereas the upper flights 21 are moving in the opposite, reversing direction. The flights 20, 21 are reciprocated over a predetermined length of travel and always reverse in the positions shown for the upper flights 21. The leading end of each flight, when reversing, has an angled face 22 to facilitate movement through material on the conveyor.

Each flight 20, 21 comprises an elongate. vertical plate 24 having a forwardly projecting bottom margin 26, in the conveying position, obtusely angled to the plate 24, and a rearwardly projecting upper margin 25 and lower margin 27. The forward face of the vertical plate 24 is provided with a uear plate 28.

The vertical plate 24 is secured by means of bars 29.

30 to a cam 35 angularly movable about a vertical pin 36 to provide for movement of the respective flight between the conveying and reversing directions. The cam has a circular outer surface with a cut-away portion defining lobes 37, 38.

Each flight 20, 21 is mounted via its cam 35 and pin 36 on a block 40, slidable along the upper surface of the base plate 10 to provide for the reciprocation of the flight. Each block 40 has a projection 41 trapping the block beneath the rail 15 and between the respective side member l, and trapping member 16.

Each block 40 forms part of a chain, as is more clearly shown in Figure 5, which is a simplification of the construction. Each block 40 has a clevis 42. 43 at opposite ends, pivoted to a spacer block 45 by a pivot pin 44. A pivot connection is shown more clearly in Figure 3 wherein the horizontal pivot pin 44 is shown passing through a clevis 42a. The pivot pin 44 connects a projection 46 of an adjacent block to the clevis b means of a ball joint 47.This arrangement allows for limitea universal movement between adjacent blocks of the chain to allow for relative horizontal and vertical articulation between the pans of the conveyor. Such articulation is necessary to alloy foF undulations in the mine floor and to allow for sequential advancement of pans alone the conveyor Tn operation, the chain is reciprocated. The resistance of material on the conveyor as the chain is advanced in the conveying direction, causes each flight to be moved to the converting position.The conveying position is defined b a stop face 50 of the flight engaging a stop face 51 on the block 40. On retraction of the chain, the resistance of material on the conveyor causes each flight to be moved to the reversing position, defined br the flight engaging a face 52 of the block 40.

Projections 39 are provided on the side members 17 for each cam 35. At the end of the retracting stroke of the chain, one lobe 36 strikes a projection 39 so as to initiate movement of the flight to the conveying position.

At the end of the advance stroke of the chain, the other lobe 37 strikes a projection, so as to initiate movement of the flight to the reversing position.

An alternative construction is illustrated for reciprocation of the upper flights 21 of Figure 1. The alternative construction is shown in detail in Figure A.

In this construction, blocks 61 are interconnected b lengths of round-link chain 60, which provide for the horizontal and vertical articulation. Each block 1 has a formation 62 at each end for receiving an end link of a length of round-like chain. The chain is reciprocated in the same way as the chain of Figure 2.

Each chain is reciprocated by means of a pair of rams at opposite ends of the conveyor. With reference to Figure 7, one ram 70 is provided to drive the chain in the conveying direction and the other ram 71 is provided to retract the chain.

Hydraulic pressure is provided from a pump 72 which feeds a main control valve 73. This valve is a solenoid operated spooi valve. Contacts are provided on the drive ram 70 to operate a cam switch (not shown) . A first contact 7 is provided to initiate reversal of the stroke of the drive ram at the end of the drive stroke, by operating a relay 77. This operates the control valve to reverse the flow to the drive ram from the pump 72. The control valve simultaneously feeds the return ram 71 to effective reverse movement of the chain. Similarly, at the end of the return stroke of the piston 70a of the drive ram, a contact 76 causes activation of the relay 77 to cause the control valve to reverse fluid floor to both rams.

Where, as in this embodiment, there are two rows of flights at opposite sides of the conveyor, it is necessary to synchronise the drive arrangements.

To this end, there is provided a synchronising relay 89 in the electrical connection to the drive side of the control valve 73. The relay is controlled by the other hydraulic circuit, so as to delay the commencement of movement of the drive ram in the conveying direction, until the drive ram of the other circuit has reached a predetermined position. Both circuits have identical arrangements. The predetermined position is determined by a contact 79 on the drive ram 70. This ensures that the two rows of flights operate in synchronism without risk of collision between the flights of one row and the flights of the other row.

The flights are reversed substantially more quickly than they are moved in the conveying direction, so that they are only briefly not working to convey material.

Quick retraction of the flights is possible, because the flights are not working against the resistance of the material on the conveyor. The quick reversal is achieved by providing a differential in effective piston area between the drive ram 70 and the return ram 71.

The top of Figure 8 illustrates the movement of the flights at one side of the conveyor and the bottom of the Figure illustrates the movement of the flights at the other side of the conveyor. The shaded portions represent the period during which the flights move in the conveying direction, while the unshaded portions represent the period of retraction of the flights. The retraction is shown to occur in approximately one quarter of the time in which the flights move in the conveying direction. It is envisaged that the retraction time may be at least two thirds of the conveying time and, preferably, at least one half of the conveying time.

It can be seen, that the arrangement is such that one row of flights is also moving in the conveying direction while the other row of flights retracts. Both rows of flights, therefore, operate together in the conveying direction for a substantial part of a cycle.

Synchronisation contacts 79 are included in the Figure to illustrate that, at this point, the other drive ram is permitted to commence movement in the conveying direction.

This point occurs at about two thirds of the stroke of the drive ram.

Where it is desired to increase the length of the conveyor, this can be achieved by using additional drive units to supplement the main drive system. It is envisaged that such additional drive units may be engaged with the chain incorporating the blocks 40, 61, at selected positions.

In Figure D, for example, there is shown a chain drive 80 connected to the blocks and itself driven by a drive sprocket (not shown). An alternative, as shown in Figure 6, is a rack 81 and pinion 82 drive. These additional drive units will be synchronised with the main drive units.

It is envisaged that the main drive units mar be electrically driven, in which case, gearing of different ratios may be used to effect rapid retraction of the flights relative to their movement in the conveying direction.

It is also envisaged that the cams 39 can be disposed with, reliance being put entirely on reistance of material on the conveyor to effect angular movement of the flights between the conveying position and the reversing position.

An alternative arrangement may provide for a braking action on the flight supports at the end of their stroke, to effect the angular movement.

In the conveyor shown, it is possible to increase the height of the flights, so as to increase the depth of material handled, without having to increase the depth of each whole conveyor pan. The flights may have extension pieces added, such as extension piece 9 shown in Figures 2 and 3 and spill plates, such as spill plate 91, may be added at the goaf and face sides.

Claims

1. Conveying apparatus comprising an elongate conveyor surface for supporting material to be conveyed and along which the material is moved, flights spaced along the conveyor surface, each flight being mdunted for pivotal movement between a conveying position extending transversely of the conveyor surface and a reversing position extending generally longitudinally of the conveyor surface, drive means for causing said pivotal movement and for reciprocating each flight longitudinally of the conveyor, characterised b control means controlling the reciprocation so that the reversing speed of the flights is substantially greater than the conveying speed.

2. Conveying apparatus according to Claim 1, wherein flights are provided at both opposite sides of the conveyor surface and the flights at each side of the conveyor surface are reversed during the period that the flights at the other side are moving in the conveying direction.

3. Conveying apparatus according to Claim 2, wherein the flights at one side of the conveyor surface are offset from the flights at the other side of the conveyor surface in the conveying direction.

4. Conveying apparatus according -to Claim 3 wherein the flights extend over more than half the transverse dimension of the conveying surface.

5. Conveying apparatus according to Claim 2, 3 or 4 including drive synchronising means to delay movement of the flights at one side of the conveying surface until the flights at the other side have reached a predetermined position in the reciprocal cycle.

6. Conveying apparatus according to any preceding claim, wherein the drive means comprises first hydraulic means for moving the flights in the conveying direction and second hydraulic means for moving the flights in the reverse direction.

7. Conveying apparatus according to any preceding claim including camming means to initiate pivotal movement of each flight from the conveying position to the reversing position.

8. Conveying apparatus according to any preceding claim, including camming means to initiate pivotal movement of each flight from the reversing position to the conveying position.

9. Conveying apparatus according to an preceding claim, wherein the flights are carried by members which are pivotally interconnected so as to provide for horizontal and vertical articulation.

10. Conveying apparatus according to Claim 9, including ball pivot connections to provide for said articulation.

11. Conveying apparatus according to Claim 9, including a round-link chain interconnecting the members to provide for said articulation.

12. Conveying apparatus substantiallv as herein described with reference to the accompanying drawings.

12. Conveying apparatus according to any preceding claim wherein the drive means is operative at opposite ends of the conveying surface and additional supplementary drive means is provided between the ends of the conveyor surface.

13. Conveying apparatus substantially as herein described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows 1. Conveying apparatus comprising an elongate conveyor surface for supporting material to be conveyed and along which the material is moved, flights spaced along the conveyor surface at both opposite sides thereof, each flight being mounted for pivotal movement between a conveying position extending transversely of the conveyor surface and a reversing position extending generally longitudinally of the conveyor surface, drive means for causing said pivotal movement and for reciprocating each flight longitudinally of the conveyor, control means controlling the reciprocation so that the reversing speed of the flights is substantially greater than the conveying speed with the flights at each side of the conveyor surface being reversed during the period that the flights at the other side are moving in the conveying direction and drive synchronising means to delay movement of the flights at one side of the conveying surface until the flights at the other side have reached a predetermined position in the reciprocal cycle.

2. Conveying apparatus according to claim 1, wherein the drive means comprises first movable means for driving the flights at one side of the conveying surface, second movable means for driving the flights at the opposite side of the conveying surface, power control means for supplying power to the first movable means, and detection means for detecting a given position of said second movable means. the power control means being actuable to supply power to the first movable means in response to the detecting means detecting the second movable means in said given position.

3. Conveying apparatus according to Claim 2, including second power control means for supplying power to the second movable means and second detection means for detecting a given position of the first movable means for initiating actuation of the second power control means.

4. Conveying apparatus according to Claim 2 or 3, wherein the drive means for the flights at each side of the conveying surface includes a hydraulic ram, the. or each, power control means comprises an electrically operable hydraulic supply valve and a relay for controlling electrical power supply to the valve, and the detection means detects a given position of a movable part of the ram.

5. Conveying apparatus according to Claim 4, wherein each drive means includes one hydraulic ram for driving the flights in the conveying direction, and a further hydraulic ram for driving the flights in the reverse direction.

6. Conveying apparatus according to any preceding claim including camming means to initiate pivotal movement of each flight from the conveying position to the reversing position.

7. Conveying apparatus according to any preceding claim, including camming means to initiate pivotal movement of each flight from the reversing position to the conveying position.

8. Conveying apparatus according to any preceding claim, wherein the flights are carried by members which are pivotally interconnected so as to provide for horizontal and vertical articulation.

9. Conveying apparatus according to Claim 8, including ball pivot connections to provide for said articulation.

10. Conveying apparatus according to Claim 8, including a round-link chain interconnecting the members to provide for said articulation.

11. Conveying apparatus according to any preceding claim wherein the drive means is operative at opposite ends of the conveying surface and additional supplementary drive means is provided between the ends of the conveyor surface.