Table of Contents
- 1 How often should hoisting limit devices be tested?
- 2 When should an upper limit switch be tested by the operator?
- 3 How much clearance should there be between the crane and any obstruction?
- 4 What is the minimum clearance between a crane and any power line rated at 50 kV or below?
- 5 What is a upper limit switch on a crane?
- 6 When should a crane or derrick inspection be carried out?
- 7 Why do you need limit switch on overhead crane?
- 8 How often do limit switches need to be replaced?
How often should hoisting limit devices be tested?
OSHA 1910.184, ASME B30. 9, B30. 20, B30. 26, and ANSI Z359 require periodic, documented inspections on slings, rigging hardware, lifting devices, and fall protection every 12 months, at minimum, and monthly to quarterly in more severe service conditions.
How often should crane limit devices be tested?
once a year
OSHA requires that all active cranes must be inspected once a year at the minimum. However, depending on the cranes usage, additional inspections will be required. Crane inspections fall under two general categories based on the intervals between inspections.
When should an upper limit switch be tested by the operator?
Response: The OSHA rule at 29 CFR 1910.179(n)(4)(i) requires that, “At the beginning of each operator’s shift, the upper limit switch of each hoist shall be tried out under no load.
How often do you have to inspect overhead cranes?
Inspection Requirements An initial inspection of the crane (new or altered) prior to initial use is required. Once placed into service, overhead cranes require two different types of inspections. Frequent inspections are done daily to monthly, while periodic inspections are completed at monthly to annual intervals.
How much clearance should there be between the crane and any obstruction?
Clearance from obstruction. Minimum clearance of 3 inches overhead and 2 inches laterally shall be provided and maintained between crane and obstructions in conformity with Crane Manufacturers Association of America, Inc., Specification No.
How do you test a limit switch on an overhead crane?
To inspect the upper limit you should be inching the load block into the limit switch. Do not go right into high speed. Go in slow speed or if you have a single speed hoist then jog the pendant so the load block is inched into the limit switch. Many manuals will suggest you to go into high speed.
What is the minimum clearance between a crane and any power line rated at 50 kV or below?
10 feet
(i) For lines rated 50 kV. or below minimum clearance between the lines and any part of the crane or load shall be 10 feet; (ii) For lines rated over 50 kV., minimum clearance between the lines and any part of the crane or load shall be 10 feet plus 0.4 inch for each 1 kV.
How do you test a crane limit switch?
What is a upper limit switch on a crane?
Hoist upper limit switches are safety devices that ensure that the hoist upper block cannot travel upward striking the drum, upper sheaves, and hoist frame.
What must be clearly displayed on any overhead crane?
The rated load of the crane shall be plainly marked on each side of the crane, and if the crane has more than one hoisting unit, each hoist shall have its rated load marked on it or its load block and this marking shall be clearly legible from the ground or floor. Clearance from obstruction.
When should a crane or derrick inspection be carried out?
Designated persons shall visually inspect each crane and derrick on each day of use for defects in functional operating components and shall report any defect found to the employer. The employer shall inform the operator of the result of the inspection.
Does a floating crane need a gong?
Except for floor-operated cranes, a gong or other effective warning signal shall be provided for each crane equipped with a power traveling mechanism. When starting the bridge and when the load or hook approaches near or over personnel, the warning signal shall be sounded.
Why do you need limit switch on overhead crane?
In addition, a limit switch keeps a crane from lifting loads above rated capacity. Another kind of limit switch prevents a hoist from reaching the upper block and rope drum. Yet another type protects motors from overheating. Without overhead crane limit switches, the potential for harm is quite high.
How to test the upper limit on a crane?
Test the upper-limit switch. Slowly raise the unloaded hook block until the limit switch trips. Visually inspect the hook, load lines, trolley, and bridge as much as possible from the operator’s station; in most instances, this will be the floor of the building. If provided, test the lower-limit switch.
How often do limit switches need to be replaced?
As they open or close electrical circuits, limit switches wear out over time. To monitor wear and replace switches before they fail, limit switches should be checked daily before a crane is used. Konecranes has conducted extensive research to determine how many uses a limit switch is physically capable of performing.
Which is the most dangerous incident of an overhead crane?
Two-blocking is one of the most dangerous incidents involving cranes, as it can snap wire ropes and cause dropped loads and other catastrophic accidents. After being tripped, the ultimate limit may require a manual reset.