GB2131377A

GB2131377A - Apparatus and method for replacing conveyor belts

Info

Publication number: GB2131377A
Application number: GB08330681A
Authority: GB
Inventors: Kenneth G Hollis
Original assignee: Vulcan Materials Co
Current assignee: Vulcan Materials Co
Priority date: 1982-12-07
Filing date: 1983-11-17
Publication date: 1984-06-20
Also published as: DE3344081A1; GB8330681D0; FR2537111A1; JPS59163209A; AU2143183A

Abstract

For replacing a worn conveyor belt (10) a take-up end of the belt is taken-up by a take-up mechanism (14) and a pay-out end of the belt is payed-out by a pay-out mechanism (16). In so doing, the belt (10) imposes a take-up resistance tending to resist the taking-up of the take-up end and a draw-out force acts to draw-out the replacement end. A force-transmitting mechanism interconnects a take-up tensioner (18) and the pay-out tensioner (20) for transmitting the take-up resistance and the pay-out force into counteracting relationship. At least a substantial portion of the take-up resistance and pay-out force is thus cancelled-out, thereby greatly reducing the power requirements of the take-up mechanism. <IMAGE>

Description

SPECIFICATION Apparatus and method for replacing conveyor belts The present invention relates to the taking-up and paying-out of an elongate member and, in particular, to an apparatus and a method for the replacement of conveyor belts.

Conveyor belt assemblies typically comprise an endless item-carrying belt mounted on a support framework, and a drive mechanism which rotates the belt in endless fashion.

In many instances, conveyor belt assemblies assume very extensive lengths, such as for example, in the conveyance of ore (e.g., coal) at a mining or processing site. Such belts typically comprise a series of interconnected belt sections which can extend great distances horizontally and/or at an inclination to horizontal.

Belts of extensive length are relatively heavy, a characteristic which must be dealt with when replacing a worn belt or belt section. Typically, and with reference to Figure 1, a belt 10 or section of the belt is replaced by (i) disjoining the belt at a location 12, (ii) connecting one end of the now disjoined belt to a power driven wind-up roll 14, (iii) connecting the other belt end to a replacement belt on a replacement roll 16, and (iv) winding-up the worn belt or belt section upon the power winder while simultaneously paying-out an equivalent replacement belt or belt section from the replacement belt roll 1 6. Both belt ends travel around a guide pulley 17, 19.

It will be appreciated that in the case of an extensive and heavy belt, there are considerabie forces which must be dealt with. For example, in Figure 1, a slope belt installation is depicted which can be used, for example, in a mine shaft for transferring ore upwardly to the ground surface.

The belt comprises an upper working flight 26 and a lower return flight 28. It will be appreciated that the effects of gravity acting upon the belt flights produce forces F' and F" of relatively high magnitude which are transmitted to the wind-up and pay-out rolls 14, 1 6 respectively. Thus, it is necessary for the wind-up roll to exert substantial wind-up forces to overcome the resistance force F' before taking-up the belt, and for the pay-out belt to be strongly braked to prevent runaway of the replacement belt under the drawing-out force F". These requirements have resulted in the need for relatively expensive, bulky, heavy duty equipment. For example, a number of hydraulic winders may have to be connected in series in order to generate sufficient wind-up forces to overcome the initial belt resistance F'.Also, brakes are conventionally provided to retard or stop the pay-out of the replacement belt, such a brake on a head 30 for example.

This type of equipment is costly and its use adds considerable time, difficulty, and expense to the overall belt-exchange operation.

It will be appreciated that the wind-up resistance force F' and the draw-out force F" are generated not only in slope belt installations, but also in horizontal installations. That is, the occurrence of belt sag which is typical of horizontal installations (and also slope instaliations), especially in the return flight, creates a wind-up resistance and an unwinding or draw-out force which must be overcome by the winder and brake.

It is, therefore, an object of the present invention to minimize or overcome problems of the types described above.

Another object is to provide novel belt exchange methods and apparatus whereby the wind-up resistance and draw-out force are overcome in a simplified, inexpensive manner by arranging that they effectively counter-act each other.

A further object is to enable a worn belt section to be wound-up, and a replacement belt section to be unwound, with a minimal expenditure of energy.

According to the invention there is provided apparatus for taking-up one end of an elongate member while paying-out another end of the member, wherein a take-up resistance acts against said one end to oppose the take-up, and draw-out force acts against said other end to induce the pay-out, including force-transmitting means for transmitting said draw-out force into counteracting relationship with said take-up resistance.

For replacing at least a portion of a conveyor belt, a take-up end of the belt is taken-up by a take-up mechanism, and a pay-out end of the belt is payed-out by a pay-out mechanism such that the belt imposes a take-up resistance tending to resist the taking-up of the take-up end and a draw-out force tending to draw-out the replacement end. A force-transmitting mechanism interconnects the take-up mechanism and the pay-out mechanism for transmitting the take-up resistance and the pay-out force into counteracting relationship.

In this manner, at least a substantial portion of the take-up resistance and pay-out force is cancelled out, thereby greatly reducing the power requirements of the take-up mechanism.

Preferably, the take-up means comprises a take-up tensioner including at least one roll around which the member extends, the pay-out means comprises a pay-out tensioner including at least one roll around which the member extends, and the force-transmitting means operably interconnects said rolls.

Preferably the force-transmitting mechanism interconnects those rolls by wrapping an endless belt around sprocket wheels which are connected to the respective rolls.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings in which like numerals designate like elements, and in which: Figure 1 depicts a conventional arrangement wherein a conveyor belt of a sloping variety is being replaced by means of a conventional windup roll and replacement roll, Figure 2 is a view similar to Figure 1, of apparatus according to the invention, schematically depicting a force-transmitting mechanism displayed in a conveyor system, and Figure 3 is a side elevational view of the forcetransmitting mechanism of Figure 2.

Figure 1 depicts the afore-described slope belt installation in which an endless conveyor belt 10 includes an upper working flight 26 and a lower return flight 28. The term "belt" as used herein is tended to include all types of elongate conveyor members, including those which present a solid (non-perforated) surface, as well as those which are perforated, e.g., a mesh type of belt. The belt extends around an upper head pulley 30 and a lower taii pulley 32. A conventional support framework (not shown) is provided to support and guide the belt. This type of slope belt, which is inclined relative to horizontal, can be employed, for example, in an ore mine to convey ore upwardly to a mine portal 36 at the ground surface 38.

A conventional belt tensioner pulley mechanism 40 is provided to maintain a uniform tension in the belt.

As described earlier herein, a belt replacement mechanism is connected to the ends of the belt.

That is, after the belt 80 is disjoined, one end of the belt is connected to the wind-up rolier 14 of a take-up assembly, and the other belt end is connected to the replacement belt of the pay-out or replacement roll 1 6 of a pay-out assembly.

It is necessary for the drive motor of the windup roll to be able to overcome any force F' which resists belt take-up, as may be created by the weight of the working flight of the belt. Similarly, brakes are provided for resisting or retarding excessive unwinding speeds of the replacement roll under the influence of an unwinding or drawout force F" as created by the weight of the return flight of the belt.

In the depicted slope belt installation, the magnitudes of the take-up resistance F' and the draw-out force F" multiplied by the effects of gravity due to the inclined nature of the belt. For a similar belt in a horizontal installation the take-up resistance and draw-out force would result from the weight of the belt as the belt sags, mainly in the return flight.

It will be appreciated that, heretofore, the energy capacities of the wind-up motor and the brakes have been necessarily high in order to overcome those forces F', F".

In accordance with the present invention, however, those forces F', F" are overcome with a minimal expenditure of energy by interconnecting the wind-up assembly and pay-out assembly in such manner that the draw-out force F" and takeup resistance F' are caused to counteract one another.

The take-up and pay-out assemblies of the present invention each include a tensioner mechanism 18, 20 (Figures 2, 3) around which the belt passes. With reference to Figure 3, the wind-up tensioner 1 8 comprises a group of rolls, preferably three rolls 42, 44, 46 which are rotatable about parallel horizontal axes. A first two of the three rolls 42, 46 are vertically superimposed, and the middle third roll 44 is horizontally offset and vertically staggered relative to the other two rolls. The third roll 44 has its axle 48 connected to a fluid motor such as a hydraulic cylinder 50 which is operable to displace that axle within a guide 51.The third roll 44 thus constitutes a tensioner roll in that it is displaceable relative to a plane containing the axes of the other two rolls 42, 46. This occurs since the belt 10 is wrapped in serpentine fashion around the rolls 42, 44, 46. Upon displacement of the tensioner roll 44, the belt is forced tightly against all of the rolls to prevent relative slippage therebetween.

A similar arrangement of three rolls 52, 54, 56 and fluid-actuated motor 58 is provided for the other end of the belt 10 which is being let-out. It will be understood that the "other end" of the belt includes the replacement belt 1 OA which is attached to, and thus forms a part of, the original belt.

A conventional power wind-up motor(s) (not shown) is connected to the wind-up roll to windup the working flight.

Interaction between the forces F', F" is accomplished by means of a force transmitting connection between rolls of the take-up and payout tensioners 18, 20. In this regard, sprocket wheels 62, 66 are formed as parts of the first and second rolls 42, 46 of the wind-up tensioner, and sprocket wheels 72, 76 are formed as parts of the first and second rolls of the pay-out tensioner 20.

A first endless chain 78 interconnects the pair of first sprocket wheels 62, 72 and a second endless chain 80 interconnects the pair of second sprocket wheels 64, 74. An adjustable tensioner pinion 82, 84 engages each chain.

In order to produce sufficient tension in that portion 1 OA' of the replacement belt located upstream of the upper sprocket wheel 72 to urge the belt into firm frictional engagement with that sprocket wheel 72, a friction brake 75 is provided.

This brake 75 comprises a pair of clamping elements 77, 79 which are urged together by any suitable power device to frictionally brake the travel of the replacement belt 1 OA to create the requisite firmness of contact between the belt 1 OA and the sprocket wheel 72.

It will be appreciated that with the conveyor system at rest, the initial take-up resistance F' acts, via the belt 10, upon the first and second rolls 42, 46 of the take-up tensioner in a manner tending to rotate those rolls and their associate sprocket wheels with a torque T' in a clockwise direction as viewed in Figure 3. On the other hand, the initial unwinding or draw-out force F" acts upon the first and second rolls of the pay-out tensioner in a manner tending to rotate those rolls and their associate sprocket wheels with a torque T" in a counterclockwise direction as viewed in Figure 3. The force transmission chains 78, 80 transmit these torques T', T" into opposing, counteracting relationship. If the opposing torques T', T" are equal, as will generally be the case, then a full-cancel!ing of the torques occurs.

Assuming that the torques completely cancelout each other, it will be appreciated that upon start-up of the wind-up roll 14, only a minimal wind-up force needs to be generated.

It will be appreciated that the take-up and payout systems can be interconnected in other ways for cancelling-out the opposing forces. For example, only one roll in each of the tensioners could be interconnected. Alternatively, or additionally, a direct connection between the wind-up roll and the pay-out roll could be established. Also, force transmitting linkages other than chains could be provided, such as gear linkage.

Furthermore, as noted earlier, the present invention is applicable to conveyor systems of the non-sloped (horizontal) type, in order to counteract the wind-up resistance and the unwinding forces generated mainly by the belt sag which usually occurs, especially in the return flight.

It will be appreciated from the foregoing that by cancelling-out at least a substantial portion of the wind-up resistance and unwinding force, the energy requirements of the take-up motor are greatly reduced. The apparatus and method according to the present invention can be employed during the replacement of an entire belt, or merely of one or more sections thereof.

In operation, a belt 10 which is to be partially or wholly replaced, is disjoined in the region 12 with a take-up end connected to the wind-up roll 14, and a pay-out end attached to a replacement belt 1 OA of the replacement roll 16. The belts 10, 1 OA will be considered as one belt since they are interconnected. The naturally occurring wind-up resistance F' acts upon the rolls 42, 44 of the take-up tensioner 18, and the naturally occurring unwinding force F" acts against the rolls 52, 56 of the pay-out tensioner 20. These forces F', F" are placed in counteracting relationship by the sprocket chains 78, 80 which interconnect corresponding rolls of the two tensioners 1 8, 20.

As a result, the take-up resistance F' and draw-out force F" can be cancelled-out thereby greatly reducing the energy requirements of the wind-up roll. Consequently, the equipment employed to replace the belt is less bulky, lighter, and less expensive than the equipment heretofore required.

Claims

1. Apparatus for taking-up one end of an elongate member while paying-out another end of the member, wherein a take-up resistance acts against said one end to oppose the take-up, and draw-out force acts against said other end to induce the pay-out, including force-transmitting means for transmitting said draw-out force into counteracting relationship with said take-up resistance.

2. Apparatus according to Claim 1, comprising take-up means for taking up said one end and payout means for paying-out another end of said member, and wherein the force-transmitting means interconnects the take-up means and the pay-out means.

3. Apparatus according to Claim 2, for replacing at least a portion of a conveyor belt, wherein a take-up end of the belt is taken-up by the take-up means, and a pay-out end of the belt is payed-out by the pay-out means, such that the belt imposes the take-up resistance tending to resist the takingup of said take-up end of the belt, and the drawout force tending to draw out the replacement end of the belt, and the force-transmitting means is operable to transmit the take-up resistance and the pay-out force into counteracting relationship.

4. Apparatus according to Claim 2 of Claim 3, wherein the take-up means comprises a take-up tensioner including at least one roll around which the member extends, the pay-out means comprises a pay-out tensioner including at least one roll around which the member extends, and the force-transmitting means operably interconnects said rolls.

5. Apparatus according to Claim 4, wherein the rolls are each mounted coaxially with sprocket wheels, and the force-transmitting means comprises an endless belt extending around the sprocket wheels.

6. Apparatus according to Claim 4 or Claim 5, wherein said take-up means comprises a powerdriven wind-up reel.

7. A method of taking-up one end of an elongate member while paying-out another end of the member, wherein a take-up resistance acts against said one end to oppose the take-up and draw-out force acts against said other end to induce the pay-out, comprising transmitting the draw-out force into counteracting relationship with the take-up resistance.

8. A method according to Claim 7, wherein said member comprises a conveyor belt, at least a portion of which is to be replaced by taking-up said one end on a take-up mechanism and payingout a corresponding portion of a replacement belt from a pay-out mechanism.

9. A method according to Claim 8, wherein the draw-out force is transmitted into counteracting relationship with the take-up resistance by operably interconnecting the take-up mechanism and the pay-out mechanism.

1 0. Apparatus for taking-up one end of a conveyor belt while paying-out another end of the belt, substantially as herein described with reference to Figures 2 and 3 of the accompanying drawings.

11. A method of taking-up one end of a conveyor belt while paying-out another end of the belt, substantiaily as herein described with reference to Figures 2 and 3 of the accompanying drawings.