The double-hook electric hoist uses the same motor to drive two different sprockets to drive the chain up or down at the same time. It can accurately ensure that the rising or falling speed of the two hooks is consistent. It is suitable for lifting some large workpieces that cannot be lifted with one lifting point.
This product is the most suitable for lifting applications requiring two lifting points for a wide load or retaining a level lifting. For special requirements such as dual speed or curve beam, consult with the nearest DAWSON dealer.
ALWAYS:
• Store and handle power operated blocks correctly.
• Inspect the block and accessories before use and before placing into storage.
• For top hook suspension, use hooks that are fitted with safety catches or mouse the hook and ensure the support fits freely into the seat of the hook.
• For trolley suspension, ensure the trolley is correctly set for the beam width.
• Check that the bottom hook will reach its lowest point without running the chain or rope fully out.
• Raise the load just clear then halt the lift to ensure the integrity of the block before continuing with the lift. If the block has more than one speed, start in the slow speed.
NEVER:
• Expose power operated blocks to chemicals, particularly acids, without consulting the supplier.
• Expose power operated blocks directly to the elements, water spray, steam etc without consulting the supplier.
• Replace the load chain or rope with a longer one without consulting the supplier.
• Use the load chain or rope to form a sling.
• Change motions without first allowing the motor to stop.
• Allow persons to ride on power operated blocks.
Selecting the Correct Block
Power operated blocks are available in a range of capacities, designs and suspensions with electric or pneumatic power options. Select the block to be used and plan the lift taking the
following into account:
Type of block - chain, wire rope - electric, pneumatic - class of use - capacity and range of lift etc.
Type of suspension - hook, trolley, fixed.
Speeds and control - single speed, dual speed - pendant push button, pull cord, remote etc.
Power operated blocks are designed for vertical lifting only.
Consult the supplier if the block is to be used in areas of high risk, exposed to the elements, water, steam etc, with hazardous substances, eg acids or chemicals, or subjected to extremes of temperature.
Storing and Handling Power Operated Blocks
Never return damaged blocks to storage. They should be dry, clean and protected from corrosion.
In the case of blocks used for temporary applications, store them on a purpose made rack or suspended from their top suspension fitting. Trailing cables, pendants etc may be removed, identified and stored separately to prevent loss or damage whilst in store. In the case of blocks left in situ, park the block in a suitable
position so that it is protected from damage and does not present a danger. Raise the bottom hook so that it is not a danger to persons or liable to become accidentally engaged. Isolate the power supply.
Installing and Commissioning
Follow the specific instructions for installation and commissioning issued by the supplier and the general
requirements given overleaf. Ensure the controls work in the correct direction and that motion limits are set and operate correctly. If the block fails to operate correctly contact the supplier.
Using Power Operated Blocks Safely
Do not use defective blocks, slings or accessories. Check the slinging arrangement, that the block is safely rigged, that the chain or rope is not twisted and that the load is free to move. Raise the load just clear, halt the lift to ensure the integrity of the block, slinging arrangement etc. Always commence lifting in the slow speed. Avoid unnecessary inching of the load. Check the travel path is clear and that you have a clear view so as to avoid accidental hook engagement or collision. Follow any particular site safety rules applicable to the movement of suspended loads. Keep fingers, toes etc clear when lowering loads.
In-service Inspection and Maintenance
Follow the specific instructions for maintenance issued by the supplier. These should be incorporated into the site maintenance programme observing any particular needs due to the site or working conditions.
Regularly inspect the block and, in the event of the following defects, refer the block to a Competent Person for thorough examination: operational faults; block will not lift; slips back; motion commands reversed; over-runs when command released; wear; damage to trolley, hooks and fittings; damaged, worn or corroded chain or rope; other visible defects.
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