PORTABLE CONVEYOR BELT LIFTER
FIELD OF THE INVENTION
[00013 The present invention relates to a portable conveyor belt lifter,
[0002] The present invention s particularly applicable to a portable conveyor belt lifter for use in lifting a section of an endless conveyor belt used in conveying bulk materials, such as iron ore and coal.
BACKGROUND TO THE INVENTION
[0003] Endless conveyors are used throughout the world to efficiently transport bulk materials. Such conveyors are commonly used to transport bulk materials over long distances.
[0004] Mined natural resources, such as iron ore, coal, bauxite, mineral sands, and agricultural produce, such as grain, are often transported by endless conveyor.
[0005] The conveyor belts are typically formed of a long flexible rubberised material formed into a loop and supported on roller carrier/idler frames to carry the material. Each idler frame usually has at least one central horizontal roller between angled rollers forming a cradle shape for the belt to rest in when loaded.
[0006] One or more drive rollers or drums are provided to mov the conveyor belt, usually a drive roller/drum is provided at one end of the conveyor. Return rollers can be provided with longer run conveyors to support the empty conveyor belt after the material has been discharged,
[0007] The conveyor belt is either sectional, with joins at specific distances or has one join connecting the two ends of the belt.
[0008] Like many components of industrial or commercial equipment, the conveyor needs servicing or repair from time to time. The belt itself can become damaged and a section need replacing, or one or more rollers may start to fail (usually the roller bearings f ail) and the roiler(s) need replacing.
[0009] Particularly when one or more rollers in an idler frame needs inspecting or replacing, it is normal practice to shutdown operation of the conveyor (for occupational health and safety reasons) before allowing personnel access to the roller(s) for servicing or replacement. Roller failure during running of the conveyor can be disastrous.
[0010] A failed roller can rip the conveyor belt, causing the material being conveyed to be dumped off the conveyor, burying the adjacent idler frames and rollers, causing more damage and long term shutdown until all of the damage is repaired and the spilt materia! cleared away. This leads to protracted shutdown and loss of productivity.
[001 1] With the shutdown conveyor belt resting on the rollers, particularly when the conveyor belt is still loaded with material being conveyed, it is necessary to lift the conveyor belt up to give clearance to the idler frame for access to the rollers, particularly the central horizontal roller.
[0012] For many years ver simple hand operated and mechanical tools and equipment have been used to Sift a belt for access to the rollers. Often heavy plant, such as a mobile crane vehicle, is brought in to lift the belt. This creates a delay waiting for the crane to arrive on site and involves more personnel to effect the repair, thereby increasing the cost and extending the repair time.
[0013] Other attempts at simpler, lo cost, ways of lifting a conveyor belt have been to use vehicle bottle jacks of the type designed to lift vehicles to change tyre or wheel. Suc practices are inherently unsafe, not least because the bottle jacks are not specifically designed for lifting conveyor belts and there is an extreme risk of
overloading the lifting capacity of the jacks because of the overburden weight of the material on the conveyor belt.
[0014] The present invention has been developed with such problems in mind. It would be desirable to provide conveyor belt iifting equipment that avoids the need for a vehicular crane or highly specialised personnel.
SUMMARY OF THE INVENTION
[0015| With the aforementioned in mind, in one aspect the present invention provides a portable conveyor belt lifter including first and second supports, each said support for positioning upright at an opposed lateral side of a longitudinally extending conveyor belt , a cross brace to extend across the conveyor belt and brace the first and second supports, an elongate Iifting member to extend under the conveyor belt and to connect between the first and second uprights, and iifting means to effect upward movement of the elongate Iifting member to thereby lift the conveyor belt.
[0016] The portable conveyor Sifter may be provided as a set of individual components readily transported to site and erected at the conveyor. The convenient arrangement of components means that they can be readily transported in the back of a utilit vehicle, in a trailer or manually carried by personnel. The components can be provided in containers, such as bags or cases, to assist safe transportation to site and to ensure all of the necessary components are present.
[0017] One or both of the first and second supports may include a powered ram. For example the first and /or second support may include a piston slidably received in a cylinder. Pressure, such as hydraulic or pneumatic pressure, from a. supply may be used to extend the or each ram. Preferably, the cylinder portion is retained statically upright while the piston is extended upward.
[00183 Each of the supports may be powered by an electrical actuator, such as a motor driven actuator, associated with each support. Electrical power, such as from
a mains electrical supply or a portable or static generator, or from a portable electric power pack, may be provided and electrically connected to each electric actuator and controlled to operate the lifting and, optionally, lowering of each support. Each electrically operated support can include an electric motor driven lifting means, such as a rack and pinion type drive whereby the motor drives a cogwheel which in turn drives the rack upwards and which is connected to the extending portion of the support. That extending portion of each support is connected to the cross brace and to the elongate lifting means, such that the supported conveyor belt lifts during actuation of the respective lifting means.
[0019] Respective control of the electric actuators, hydraulic or pneumatic rams, or of manually operated jacks, helps to maintain the conveyor level during lifting, and can be used to control rate, amount and angle of lift.
[0020] The hydraulics for actuating the lifting means can be activated by a manual pump or the power pack.
|0021] Alternatively, mechanical lifting jacks can be operated by either AC or DC motors, which can be incorporated into each support or separatel mounted to each support as a drive means as required.
[0022] Many of the components of the portable conveyor belt lifter, such as the cross brace, supports and rigid bar attached to the flexible lifting member, may be formed or fabricated out of aluminium, carbon fibre or chrome molybdenum (chrome moly) for strength with lightweight transportable characteristics.
[0023] Lowering the conveyor belt can b controlled by resistance within the portable belt lifter system, such as by springs, slow release of hydraulic or pneumatic pressure controlled by one or more valves, or motor resistance, or a braking system physically acting on the extended (now retracting during lowering) portions of the supports.
[0024] Hydraulic or pneumatic pressure may be provided by a respective hydraulic or pneumatic power pack, which may be electrically driven to operate a respective hydraulic or pneumatic pump.
[0025] Preferably such a power pack may be battery powered, such as by onboard batteries, or may connect etectricatiy to an onsite electrical power supply. The batteries may be rechargeable batteries.
[0026] One or more hydraulic or pneumatic feed lines may operativeiy connect the first and second supports to the hydraulic or pneumatic power suppiy. Preferably at least one feed line extends laterally under the conveyor belt to connect one of the said supports to the supply at the opposite side of the conveyor belt.
[0027] One or more valves may be provided in the feed lines to control supply of hydrauiic'pneumatie pressure to the uprights. Thus pressure, and therefore amount of extension of each upright can be controlled to ensure the section of belt is lifted evenly and safely.
[0028] Each of the first and second supports may include or be attached to a lower portion for mounting the respective support to a ground support. The ground support may include a rail extending alongside the conveyor.
[0029] For an upright first or second support, an upper end thereof may include a head member. The head member may be permanently attached to the respective upright or may be removably attachable for ease of assembly and transport. The head member may connect to the cross brace and may provide attachment for an end of the elongate Sifting member,
[0030] The cross brace may inctude or be an elongate f lexible member, such as a rope, strap, chain or cable, or combinations: thereof .
[0031] Alternatively, the elongate lifting member may include a resilient member, such as a carbon fibre beam, which may preferably be pre-curved to a degree to provide a curved shape resembling the curved cradle shape of the conveyo belt.
[0032] The elongate lifting member releasably attaches to one or both of the upper ends of the first and second supports, such that the elongate lifting member moves upwards when the supports are extended, it will be appreciated that the extending portion of each said first and/or second supports may be provided as a ram forming essentially what is the main upright body of each of the supports, but may alternatively be a ram/jack mounted to the respective support. For example, one or both of the supports may have a hydraulic, pneumatic or eieetrically powered ram mounted to one end of each support, preferably the upper end when the supports are erected upright across from one another either side of the conveyor belt.
[0033] Conveyor belts can vary in width depending on the application and location. Widths vary typically between 500mm and 2400mm. though other widths, smaller, larger or intermediate, are envisaged. Different lengths of elongate lifting member and the cross brace may be provided to accommodate for differing widths of conveyor belt. Longer elongate lifting member and cross brace can be used with relativel wide belts, whilst shorter lengths of elongate lifting member and cross brace ma be used with narrower width conveyor belts.
[0034] Width of the conveyor belt and laden weight of the belt per metre of length of the belt can be used to determine the required specification of the portable conveyor belt lifter, including the specification of th powe pack. The specification needs to be able to cope with safely lifting the !aden conveyor belt.
[0035] It will be appreciated that the effective length of the cross brace and/or the elongate lifting member may be adjustable. For example, the cross brace ma be telescopic, with an ability to lock at a chosen length.
[0036] Alternatively, the cross brace ma include selectable engagement positions which selectively coincide with a respective engaging point provided for each said support, or vice versa. Thus, if the cross brace is overly long for a particular application, the cross brace can still be used provided the range of selectable engagement positions and the respective engaging point engage together to lock in the cross brace in a fixed position and maintain the desired separation between the first and second supports across the width of the conveyor belt.
[0037] Likewise, the elongate fitting member may include length adjustment, such as by a selection of loops along a strap or a length of chain at one or both ends thereof whereby the chain links can be used as selective connection means to vary the effective length of the elongate lifting member.
[0038] The portable conveyor belt lifter may be provided as a kit of parts.
[0039] The portable conveyor belt lifter may conveniently and quickly be assembled in situ and be powered b a power pack transported with the lifter assembly.
[0040] The belt can be readily lifted, the rollers underneath Inspected and/or serviced/replaced, and the conveyor restarted, with minimal personnel needed to assemble, operate and dis-assemble the portable conveyor belt lifter, and associated downtime of the conveyor reduced, compared to using a crane and more personnel.
[0041] Preferably, the first and second supports (e.g. A and B in the figures and described below} may be identical or almost identical.
[0042] However, one of the first or second support, preferably support A, may include an attachment means (e.g. a hook) that enables the user to adjust the length of the sling depending on the belt width and also to tighten up the sling to remove slack for maximum lift. Thus, the sling shackle of support 8 can also be permanently
attached to that support B, and therefore the sling can remain permanently attached to support B.
[00433 Preferably bot first and second supports have synchronised hydraulic cylinders with a unique ram without a seal.
[00443 Instead of a seal each ram has one or more engineered grooves on it to ensur equal volumes of oil flow between the bottom and top section of the ram, removing the need for a seal to push the oil and requiring less pressure whilst providing more accuracy. It also removes the requirement to service the cylinder too often, to change the seal and possible wear on the cylinder walls.
[0045] Each cylinder associated with each of the first and second supports may also have one or multiple springs inside to ensure that the lowering speed/rate of each ram is rapid and goes ail the way down to a minimum height.
[0046] The clamping arrangement to the stringers ma include a push on fit, which reduces overall weight of the portable belt lifter system by reducing the amount and size/weight and complexity of mounting components. Mounting can be by way of a push on fit 'C shaped channel forming a lower mounting means for each upright support.
[0047] A solid support can be provided to augment the flexible elongate member for improved lifting stability. For example, the elongate flexible member can pass through a tube, preferably a rigid metal, composite or plastic tube, to provide additional strength and lift stability to the conveyor, especially when the conveyor is loaded and therefore relatively heavy.
[00483 Alternatively, the rigid member can include a solid bar or hollow tube which attaches to or the elongate flexible member threads through to be largely external of the rigid member when in use.
BRIEF DESCRIPTION OF THE DRAWINGS
(0049] One or more embodiments of the present invention will hereinafter be described with reference to the accompanying drawings, in which:
[0050] Figure 1 shows a portable conveyor lifter according to an embodiment of the present invention in perspecttve and in position for lifting a section of conveyor belt.
[0051] Figures 2a, 2b, 2c and 2d show respective front, plan, isometric and side elevations of a portable conveyor belt lifter according to an embodiment of the present invention.
[0052] Figures 3a-3d show details of one of the first or second supports according to an embodiment of the present invention.
[0053] Figures 4a-4d show details of the first or second supports with a head member attached thereto, according to an embodiment of the present invention.
[0054] Figure 5 shows an alternative embodiment of the portable belt lifter of the present invention.
DESCRIPTION OF PREFERRED EMBODIMENT
[0055] An embodiment of a portable conveyor belt lifter of the present invention is shown in Figure 1.
[0056] A typical conveyor system includes structural {stringer) members 1 running either side of the conveyor along its length. These stringers provide the main structural support for idler roller frames (not shown in Fig 1) spaced along th length of the conveyor underneath the belt 17. The idler roller frames are omitted in Fig 1 in
order to more clearly show the components and positioning of the portable conveyor belt lifter.
[0057] Each of the first and second supports A, B is releasabiy attached to a respective stringer by a respective foot portion 2a, 2b. if will be appreciated that the first/second support can be either releasabiy retained or permanently attached to its respective foot portion. The foot portion provides a base that helps to spread load into the respective stringer and provide a stable upright mounting position for the respective support.
[0058] Each of the foot portions is releasabiy attached to the respective stringer by a clamp means 3a, 3b which engages to the upper lip portion 1a, 1b of the respective stringer. A release handle 4a, 4b on each of the clamp means is operativeSy attached to a clamp means release mechanism of each clamp means.
[0059] Each of the foot portions houses a hydraulic cylinder arranged to extend under application of hydraulic pressure. A pneumatic or electrically powered cylinder could alternatively be provided.
[0060] An outer tube 5a, 5b is positioned on a respective foot portion and over the hydraulic cylinder. A push tube or rod 6a, 6b is inserted into the respective outer tube. Application of pressure to the hydraulic cylinders.) causes the respective push tube or rod to extend upwards out of the outer casing. Each push tube or rod engages with an adapter provided on each hydraulic cylinder to ensure correct positioning and operation.
[0061] Hydraulic pressure (or pneumatic pressure as appropriate) is supplied to the cylinders from a power pack (not shown) through feed lines 18,19, one to each of the cylinders, preferably from just one side of the conveyor i.e. feed line 19 extends across under the conveyor.
[00823 Each of the upright first and second supports A, B is provided wit a head member 9, 10. In the embodiment shown, head member 9 differs from the other head member 10 in that the head member 9 has an open ended passage 9a therethrough that allows the cross brace tube 11 to pass through, whereas head member 10 is blanked off at a rear end 10a. This allows positioning and adjustment of the cross brace to suit varying widths of conveyor belt within certain parameters. If the cross brace tube 1 1 is not long enough, a longer cross braced tube can be selected.
[0063] It will be appreciated that, although the embodiment described with reference to Figure 1 has a cross brace tube, that cross brace could be a solid beam, or a sectional beam of tubes and solid sections. It is convenient to make the cross brace a generally hollow tube to reduce weight, which provides for greater ease of installation and also handling and transport. The cross brace may be circular or other shape in cross section, such as a square section tube or bar. The cross brace may be formed of or incorporate carbon fibre for iightness whilst retaining sufficient strength.
[0064] The cross brace tube 1 1 has a number of connection points 11 a to allow a choice of effective length of the cross brace. The cross brace tube is shown in Fig 1 using its longest effective length. A locking pin 15 engages and locks the cross brace tube to the head member 9 on the far side of the conveyor. This ensures rigidity and safety of the assembly. A safety pin 16 ensures that the locking pin does not come out until required.
[0065] One end of a sling 20 is attached by a shackle 12 to the head member 9 on the far die of the conveyor. The sling can include rope, strap, webbing, chain or cable etc. The sling passes under the conveyor belt and is attached by a sling length adjuster 14 (such as a length of chain connected to a ehain-shortener). Slack in the sling can be taken up before the hydraulic cylinders are operated. This ensures that the sling is close up under the conveyor belt and reduces the amount of
extension of the cylinders that would otherwise be needed if the sling was simpl loose under the conveyor belt.
[00663 Once the hydraulic cylinders are extended, the push tubes or rods 6a, 6b rise, which lifts the head members and cross brace tube as well as the sling. This ensures that the belt liftin operation is safe and the assembly is rigid.
[0067] Once the push tubes/rods are raised, support extension locking pins 7a, 7b can be inserted through holes provided in the outer cylinders 5a,5b. This locks the push tubes/rods in position in the event of hydraulic pressure failure. The conveyor belt will remain lifted even if power or hydraulic pressure is removed. This ensures safety for personnel working on the rollers under the conveyor belt. Safety pins 8a.8b ensure that the support extension locking pins remain in position until required.
[0Q68] Once work on the conveyor rollers is completed, and the belt is to be lowered, lowering is a reversal of the lifting procedure. Safety pins 8a.8b and upright support locking pins 7a,7b are removed, hydraulic pressure is gradually and safely released. Pressure release is effected by valve control at the power pack, One or both of the hydraulic cylinders can be released at any one time by judicious use of the control valve(s), thereby ensuring even and controlled lowering of the conveyor belt.
[0069] Figures 2a to 2d show respective front (Fig 2a), plan (Fig 2b), isometric (Fig 2c) and side (Fig 2d) views of another embodiment of the portable conveyor belt lifter of the present invention. The conveyor belt is not shown. However, the portable conveyor belt lifter would span the conveyo belt the same as in Figure 1.
[0070] In this embodiment, the lower foot portions 2a, 2b supporting the upright support tubes 5a, 5b with the push rods/tubes 6a, 6b inside are releasably mounted to the stringers 1 a, 1 b by releasable attachment means 3a, 3b provided towards an inside face of the stringers. That is, the attachment means are inboard and
underneath relative to the conveyor belt rather than being on the outside faces of the stringers.
[0071] Figures 3a to 3d show detail of a first or second support A (or B). Figure 3a shows a side view of the upright support with the outer tube 5a supported by the foot portion 2a. The push tube/rod 6a is shown inserted into the outer tube. The foot portion is formed with upright plates 22a, 22b linked by horizontal plates 24a, 24b. The upper horizontal plate 24a has a hole therethrough to receive the outer tube 5a. The lower end of the outer tube is supported on the lower horizontal plate 24b.
Vertical support plates 26a, 26b help to rigidity the support assembly and provide mounting for the hydraulic connections and release mechanism.
[0072] Figures 4a to 4d shows an alternative embodiment of the upright support A (or 8). The support includes the head portion 9a to receive and support an end of the cross member 11 (not shown). The head portion is attached (reSeasabty or permanently - depending on the application) to the upper end of the push tube/rod 6a.
[0073J As described above, the push tube/rod is moved upwards within the outer casing tube 5a by a hydraulic (or pneumatic) ram/cylinder. Alternatively, the push tube/rod could be the piston of such a ram i.e. the outer casing could form the cylinder and the central piston thereof raises the head portion to raise the conveyor belt.
[0074] Power to the lifting means associated with each upright support can be provided by an electrical supply, such as a portable electric power pack, portable generator (genset) or main powe supply. Electrical power and actuation of the portable belt lifter avoids the need fo hydraulic or pneumatic lines, connections, valves, hydraulic fluid as required, and the need for a separate petrol/gasoline or diesel powered pump for the hydraulics or pneumatics.
[0075] For an electrically powered portable belt lifting system, the reduction in the number of components also reduces overall weight and space of the system for transportation, as well as reducing cost. This means that more systems can be kept on hand ready for use or distributed around a site for immediate deployment without needing to wait for a single system to come from afar.
[0076] As shown in Figure 5, each upright support 9,10 reieasably mounts to a respective stringer 1a, 1b either side of the conveyor system. The stringers are permanent static parts of the conveyor system. The upright supports mount to the stringers by a push fit arrangement. Each of the upright supports 9,10 has or is attached to a lower mounting member 28,30.
[0077] The lower mounting member 28,30 Is in the form of a 'C shaped channel that push fits over the stringer. Weight/force applied down through the respective upright supports 9,10 when lifting the conveyor be!t 17 is applied to the stringers, which support the portable belt lifter.
10078] When assembly or disassembling the portable belt lifter, the lower mounting means 28,30 are a push fit onto and a pull removal arrangement. Each of these lower mounting means may include a locating lip 32,34 which helps with positive location and helps ensure retention of the lower mounting means to the respective stringer.
[0079] The flexible elongate member 20 can thread through a hollow tube member 36 to aid strength and lift stability, particularly when the conveyor belt 1 is loaded with material.
[0080] Alternatively, the flexible elongate member 20 can be threaded through mounting means provided on a solid or hollow relatively rigid member for similar strength and lift stability benefits.
[0081] The relatively rigid member can be formed of or include metal, such as stainless steel, carbon steel or mi!d steel, or can include a carbon composite material such as carbon fibre for high strength low weight performance.