guide to chain motors v2 - theatre safe australia
TRANSCRIPT
This product is intend for trained and competent persons and should only be considered as a guide only. TSA takes no responsibility for any information a person uses from this documentation.
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Guide to Chain Hoists
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1. Gearing 2. Electro-magnetic Brake 3. Limit Switch 4. Cable Pug In’s 5. Electro-magnetic Contactor 6. Reverse Phase Relay 7. Chain Container/Bag 8. High Strength Chain 9. Lower Hook 10. Push button cable & Cable Relief 11. Push button Switch
Standard Basic Hoist Diagram
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Dont’s• Don't operate a damaged, malfunctioning or unusually performing chain hoist.
• Don't operate the chain hoist until you have thoroughly read and understood the manufacturer’s Operating and Maintenance Instructions or Manuals.
• Don't operate a chain hoist, which has been modied without the manufacturer’s approval.
• Don't lift more than rated load for the chain hoist.
• Don't operate a chain hoist unless it has been securely attached to a suitable support.
• Don't use chain hoists with load chains that are knotted, twisted, kinked, damaged, or worn.
• Don't use the chain hoist to lift, support, or otherwise transport people, without additional or mandatory local or national safety precautions.
• Don't move a load in any manner that can endanger persons.
• Don't operate unless all persons are and remain clear of the supported load.
• Don't operate unless load is centred under chain hoist.
• Don't use limit switches as routine operating stops. - They are emergency devices only.
• Don't operate a chain hoist when it is restricted from forming a straight line from hook to hook in the direction of loading.
• Don't use load chain as a sling, or wrap the load chain around load.
• Don't apply the load to the tip of the hook or to the hook latch.
• Don't apply load if bearing prevents equal loading on all load supporting chains.
• Don't operate beyond the limits of the load chain travel
• Don't use the chain hoist’s overload limiting clutch to measure load.
• Don't leave a load supported by the chain hoist unattended unless specic precautions have been taken.
• Don't allow the load chain or hook to be used as an electrical or welding ground.
• Don't allow the load chain or hook to be touched by a live welding electrode.
• Don't remove or obscure the warnings on the chain hoist.
• Don't operate a chain hoist on which the safety placards ordecals are missing or illegible.
• Don't operate a chain hoist unless load slings or other approved single attachments are properly sized and seated inthe hook saddle.
• Don't allow your attention to be diverted from operating the chain hoist.
• Don't allow the chain hoist to be subjected to sharp contact with other chain hoists, structures, or objects through misuse.
• Don't adjust or repair the chain hoist unless qualied to perform such adjustments or repairs.
• Don't attempt to lengthen the load chain or repair damagedload chain.
• Don't drag the load chain and/or chain hook across dirty,sandy of abrasive surfaces (concrete oors).
Do’s
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• Do always keep your attention to the chain hoist and the load that it is supporting.
• Do use hook latches. Latches are to retain slings, chains, etc. under slack conditions only.
• Do make sure the hook latches are closed and not supporting any parts of the load.
• Do make sure the load is free to move and will clear all obstructions.
• Do make sure the power (and control) cables and connectors have proper stress relieves and are never fully tight during lifting or lowering movement.
• Do warn personnel of an approaching load.
• Do avoid swinging the load or hook.
• Do inspect the chain hoist regularly, replace damaged or worn parts, and keep appropriate records of maintenance.
• Do use a protective cover for the chain hoist to prevent exposure to rainfall when applied outdoors.
• Do only use factory recommended parts when repairing the unit.
• Do protect the load chain from weld splatter or other damaging contaminants.
• DO make sure that the weight of the load to be suspended is known, and in accordance to the lifting capacity of the chain hoist. In multiple lifts make sure a rigging plot is present.
• Do make sure that the hoist operator is in good physical and mental condition.
• Do check the chain hoist, suspension-hook, chain-hook, hook latches, as well as the load-chain itself, prior to each time of use for any damage, deformation or malfunction.
• Do make sure that the structure from which the chain hoist is suspended, as well as the slinging equipment is able to safely absorb the force resulting from the weight of the load and the chain hoist itself, multiplied by the dynamics of starting and stopping the lifting action. For a Prolyft hoist for example it is approximately 1.4 times the static load.
• Do check brake function by tensioning the chain hoist prior to each lift operation.
• Do shut down a chain hoist that malfunctions or performs unusually and report such malfunction.
• Do make sure hook travel is in the same direction as shown on the controls.
• Do maintain rm footing or be otherwise secured when operating the chain hoist.
• Do guide the chain hoist to take up slack chain carefully without twisting or knotting.
• Do make sure load is balanced and load holding action is secure before continuing lifting operation.
• Do always keep your attention to the chain hoist and the load that it is supporting.
• Do use hook latches. Latches are to retain slings, chains, etc. under slack conditions only.
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The use of any chain hoist presents some risk of personal injury or property damage. That risk is greatly increased if proper instructions and warnings are not followed.
Before using this chain hoist, each operator should become thoroughly familiar with all warnings, instructions, and recommendations in the manufactures requirements and manual.
Keep all documentation for hoist in a common area for full access for operators and future reference and use.
Operation Statement
Operation
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Below are the basic operation guide lines to a chain hoist:
• Ensure hoists are within appropriate test date and the load being lifted is within the hoists W.L.L
• Check there are no obstruction in the path of your hook or the load being lifted. ‘such as cables, lamps, set pieces, etc.’
• Ensure you have sufficient spotters in place to watch and assist with tag lines on the load (if required)
• Lift the load so it is just off the ground. (this enables you to check the load has been rigged correctly)
• Once you are happy with the rigging of the load, continue lift to final height
• Once at desired height E-stop the chain hoist and power down the hoist(s).
Suspending Loads vs People
The suspension of loads over people demands the highest level of rigging knowledge, equipment, and equipment maintenance. The hoist must be installed and used in accordance to local and national standards and regulations when suspending loads over people. These include the following important precautions.
1. It is preferred that the load always be tied off with an auxiliary chain or cable (‘secondary’ or ‘safety’) before access to the area beneath the load is permitted.
2. As an alternative, the system may be designed in such way that malfunction or failure of one chain hoists load bearing components does not cause load loss and/or overloading of any other chain hoists in the system. Note that in such a system, chain hoist performance and function must be monitored visually or should be monitored using load cells.
3. The use of double braked hoists is a must
4. Never operate the chain hoist while people are under the load.
Standards Overview
BGV-D8: Lowest classication in Germany. Not suitable for moving loads over persons and requiring secondary safety device (static tethers or load arrestors) to suspend loads over persons. No limit switches required, single brake, min 5:1 safety factor, load bearing clutch & brake may act via the clutch, no emergency stop required.
BGV-D8+: Enhanced BGV-D8 classication. Not suitable for moving loads over persons, but suitable for suspending loads over persons without secondary safety device. No limit switches, double brake; 8:1 safety factor, no overload, load bearing clutch not permitted, brake must act directly on drive train, no emergency stop required.
BGV-C1: Highest classication. Suitable for moving and suspending loads over persons. Operating and ultimate limits required, double brake, 10:1 safety factor, overload cutout at 120% required, underload cut-out required for group lifts, load bearing clutch not permitted, brake must act directly on drive train, emergency stop required.
BS7906 Category B: Lowest classication in the UK- Basically as per BGV-D8 but with a minimum 4:1 factor of safety.
BS7906 Category A: Highest classication – Operating and ultimate limits required, double brake, min 8:1 safety factor, load bearing clutch not permitted, brake must act directly on drive train, emergency stop required.
AS1418 Not designed for “Special Lifting Applications” – Operating and ultimate limit switches required, single brake acting directly on drive train, 5:1 safety factor, load bearing clutch not permitted, emergency stop required.
AS1418 Designed for “Special Lifting Applications” – Operating and ultimate limit switchesrequired, 8:1 safety factor, load bearing clutch not permitted, emergency stop required, either double brakes on a redundant drive train or double brakes where one brake is a full load output brake with over speed operation, suitable for man-carrying.
Things to remember
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• Even though the basic operation of a chain hoist(s) can seem simple, they can be very dangerous and should only be operated by competent persons
• Periodic maintenance should be carried out to maintain the hoists safe working condition
• Pre & post ‘use’ inspection(s) should be carried out to maintain the hoists safe working condition
• You must never go over the systems W.L.L for operations - Including any dynamic loadings that may applied.
• Your chain hoists MUST be checked over by qualified service person(s) Annually to ensure it meets the necessary manufacture & Australian Standards (AS 2550.1 & AS1418.1)
• No well maintained hoist should be noisy, squeaks and knocks are signs of wear, possible defect and could amount to larger problems if left unattended
Remember! If you are ever unsure or have any questions regarding operation or
servicing of a hoist or any rigging equipment ask a qualified person.
We are always on hand at TSA to give free advice and answer any questions you may have no matter how big or small they may
seem.
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Call Us on (07) 5574 5327
References http://www.hitachi-ds.com/hitachi-ds/en/Products/Hoist/Electric-Chain-Hoist.html
(Credit – material for this article was sourced, in part, from articles published by Jands Staging in CX Magazine)
This product is intend for trained and competent persons and should only be considered as a guide only. TSA takes no responsibility for any information a person uses from this documentation.
Please consulate a professional on the best product for your use
www.theatresafe.com.au [email protected]
www.facebook.com/theatresafeaustralia