Chain blocks are essentially hand-operated hoists. They consist of a hand chain and load chain and a set of gears to empower the user to lift a load with minimal effort. Very little has changed to the chain block design and construction since the turn of the 20th century because they work and because there isn’t much more to improve. Chain blocks are very affordable, very strong, do not require a power source, and can be transported rather easily. The average hand-carried chain block can lift a load that would otherwise require the assistance of 3 to 4 people and more questionable methods.
Chain blocks are very popular because of their utility, but their simplicity and popularity can lead to people being careless while using them. Even though the requirements for lifting equipment are pretty relaxed despite the variety of lifting equipment, they are still lifting equipment. Chain blocks are very useful but can easily lead to injuries if people do not exercise proper care while using them.
Manual chain blocks
Without a doubt, the hand-chain version is the most popular, and for infrequent lifting there are very few competitors. Chain blocks are extremely versatile and can be used to perform lifting tasks in almost any environment. Chain blocks do, however, have their limitations in regards to speed and effort. It can be a time-consuming task to perform lifts, and depending on how big the load is, the operator may have to exert a significant amount of effort. For lifts that have to be performed very frequently, this can be bothersome, and is usually the point at which they are replaced with an electric hoist.
Block capacities run from 250kg to 10 tonnes and up, but most applications use blocks ranging from 0.5 to 3 tonnes. The headroom, which is the distance between the top of the block and the load hook, is important, as it can restrict certain applications when space is limited. Low headroom blocks are made to circumvent this problem.
Electric chain hoists
With less effort, and at the push of a button, an electric chain hoist can accomplish the same task. Once lifting becomes more frequent, the advantages of speed and the ability to repeat the task become even more apparent to the user.
Most of the decisions to purchase an electric chain hoist are more related to the application than the technology. Is there sufficient power where the lifting is done? Single-phase electric chain hoists are often used to do lighter lifting tasks, while larger and more robust electric chain hoists rely on three-phase power. How high is the hoist going to lift, and how often is it going to operate? Duty rating is important, as hoists are designed to operate within a duty cycle. Does the load need to travel? Fixed hoists lift vertically. However, when combined with a push trolley (or powered trolley) on a beam, it becomes possible to move loads horizontally.
Pairing a Jib Crane and a Hoist
Chain hoists are most commonly seen on the shop floor suspended from a jib crane. A crane is a structure and a hoist is a mechanism. Hoists should be specified with cranes. A hoist’s weight is accounted for in a crane’s capacity; a hoist’s headroom is accounted for in a crane’s lifting capacity; and if a hoist runs on a trolley along a crane’s jib, the trolley should match the crane’s beam profile. The most common way to get a hoist and a crane that are incompatible is to buy the crane and the hoist independently, which is covered by our guide on free standing jib cranes (link) and applies to runways as well.
Also critical to every lift is the connection to the load, which falls into sling territory, covered by our guide on lifting slings (link).
Inspection, and the paperwork
Like every device that lifts, chain blocks and hoists fall under LOLER. In practice, this means thorough inspection at least every 12 months, a visual inspection before every use, and a legibly marked safe working load. The pre-use inspection is more critical on chain blocks that most kits because of the life a chain block has. Block chain hoists are thrown in vans, left rigged on the floor outdoors, and are often lent between trades. All of the following are common, and can be found in 30 seconds by anyone who cares to look: load chains that are stretched or damaged, hooks that have been opened out, and missing safety catches.
Records are essential too; keeping the examination report is a must, and a block with no history is one an examiner will be suspicious about. You should buy from a supplier who provides a test certificate because a cheap block with no paperwork is no longer a cheap block the first time someone requests the documentation from you.
What goes wrong
Failures are comforting because they are predictable. Blocks get overloaded because no one took the time to weigh the load, and it is easier to estimate. Hand chains are pulled at an angle instead of directly, which, yes, causes damage to the gear. Blocks are rigged from whatever is overhead, a purlin or a fork heel, instead of a truly rated point. A block that is clearly unsafe is still put to use because it still works, sort of, and no one wants to take the only block off the job.
All of these problems can be solved with the right equipment, but that isn’t the right culture. To solve a problem instead of overusing an unsafe block, you need a rated anchor point and a culture where people quarantine unsafe blocks. Blocks that are looked after do truly outlast the people who are using them.