| block and tackle |
A moveable pulley that is used to raise and lower loads. More lines on a block and tackle allow you to do more work with less effort. |
| boom |
The lifting arm of a crane or derrick. |
| bosun's chair |
A small swinging scaffold similar to a climbing harness, except that it has a rigid seat. |
| bottle jack |
A type of hydraulic jack that is placed in a horizontal position. Bottle jacks are preferred for their high leverage and ability to fit into small spaces. |
| bottom winding |
Winding rope from the bottom of the drum. Also known as underwinding. |
| breech |
The side opening in the side of the sheave opposite the rope. |
| bridge |
The part of the crane which carries the trolley. Bridges consist of girders, trucks, end ties, footwalks, and the drive mechanism that carries the trolley. |
| chassis |
The framework for supporting an object. |
| clamp |
An end fitting used to secure hardware to the end of a rope. |
| compound block and tackle |
A pulley system that consists of two or more ropes with two or more blocks. A compound system is made up of two or more simple systems. |
| crane |
A machine for lifting and moving extremely heavy loads. A crane provides both vertical and horizontal movement of heavy and oversized loads. |
| crawler-mounted |
A type of mobile crane that is mounted on a chassis with caterpillar tracks. Crawler-mounted cranes are used for jobs that require a high level of stability and traction. |
| cribbing block |
Rigid rectangular materials used to support a load as it is being lifted, moved, or leveled. |
| derrick |
A lifting device with a mast held at the head with guys or braces. Derricks come with or without a boom for use with a hoisting mechanism and operating ropes. |
| diameter |
The width of a circle. |
| drum |
A spool-like cylindrical object with flat ends extending beyond the center's diameter. Drums are used to store and spool rope. |
| flanges |
The sides that project from each end of a drum and contain the rope. |
| forklift |
A small industrial truck used for carrying, lifting, and stacking materials. |
| fulcrum |
A pivot point of a lever, or the point around which an object turns. |
| gantry crane |
A crane with a bridge supported on two or more legs running parallel on fixed rails. |
| groove |
The channel in a sheave through which rope is passed. Always choose a sheave that is at least 1½ in. wider than the rope's diameter. |
| guy |
A rope or cable that is used to secure something. |
| hoist |
A lifting device that exerts vertical forces for lifting and lowering, usually from a position that is directly above the load. |
| hook |
A lifting device used to pick up loads with eyebolts attached. Hooks are usually used with chains, hoists, and slings. |
| hydraulic jack |
A type of jack that has a pump plunger that forces a fluid through a cylinder. |
| jack |
A tool used for lifting large or heavy objects. Jacks are used for items that cannot, or should not, be lifted with a crane or hoist. |
| jib |
A horizontal arm that attaches to the boom of a crane. |
| lattice |
A reinforcing structure that provides support to the mast of a crane. |
| lever |
A type of simple machine consisting of a rigid bar that pivots on a fulcrum. Levers are used to transmit motion and alter mechanical advantage. |
| lift capacity |
The maximum lifting force of the jack. |
| lift stroke |
The difference between the fully retracted and fully extended positions of the jack. |
| lifting medium |
The component that provides the vertical raising and lowering of a load. Wire rope and chain are commonly used lifting mediums. |
| load |
The opposition to applied force, such as a weight to be carried or moved. |
| mast |
A long, vertical pole used to support a structure. |
| maximum height |
The distance from the base of the jack to the lifting element when it is fully extended. |
| mechanical advantage |
The difference between the applied force and the work accomplished. Mechanical advantage allows machines to perform more work with less effort. |
| minimum height |
The distance from the base of the jack to the lifting element when it is fully retracted. |
| mobile crane |
A crane designed to travel to different parts of a job site. Mobile cranes can be truck-mounted, wheel-mounted, or crawler-mounted. |
| moveable pulley |
A circular lever that rotates around the fulcrum. A block and tackle is an example of a moveable pulley. |
| operation type |
The type of power provided to the lifting device. Lifting devices are powered electrically, manually, or by air pressure. |
| OSHA |
Occupational Safety and Health Administration. A government agency dedicated to reducing injuries, illnesses, and deaths in the workplace. |
| overhead crane |
A crane with a movable bridge carrying a movable or fixed hoisting mechanism and traveling on an overhead fixed runway structure. |
| overwinding |
Winding rope from the top of the drum. Also known as top winding. |
| protection fan |
A structure that extends from the perimeter of the scaffold to protect people from falling objects and debris. |
| ratchet jack |
A type of jack that has a lever that raises the jack up or down with each downstroke. |
| reeving |
The process of passing rope through a sheave. When reeving, make sure the sheave and rope are appropriately sized. |
| rigging |
The process of lifting and moving heavy loads with ropes, chains, and mechanical devices. |
| roller |
A cylindrical device that rotates to move a load. Rollers are often used in combination with skids. |
| safety net |
A length of mesh installed under a scaffold to provide fall protection to workers. |
| scaffold |
A platform that riggers stand or sit on while performing work. |
| screw jack |
A type of jack that consists of a threaded cylinder that is moved up or down when the handle of the jack is turned. |
| sheave |
The freely moving wheel that is part of a moveable pulley. The sheave usually contains a groove to hold a rope or chain. |
| shell |
The outer covering on a moveable pulley. |
| simple block and tackle |
A pulley system that consists of a single line with one or more blocks. |
| skid |
A wooden plank used for form tracks for moving heavy objects. Skids are used in combination with rollers. |
| socket |
A type of fitting that can be installed and removed quickly and easily. |
| stationary scaffold |
A fixed scaffold that is built on the job site. Stationary scaffolds are often used for long-term or large-scale jobs. |
| suspended crane |
A crane with a movable bridge carrying a movable or fixed hoisting mechanism and traveling on an overhead fixed runway structure. |
| suspended scaffold |
A mobile scaffold that is suspended from ropes or cables. Also known as a swinging scaffold. |
| suspension type |
The mounting or method used to suspend the hoist. Common suspension types include hook mounted, lug mounted, trolley mounted, and wall mounted. |
| swinging scaffold |
A mobile scaffold suspended from ropes or cables. Also known as a suspended scaffold. |
| top winding |
Winding rope from the top of the drum. Also known as overwinding. |
| tower crane |
A stationary crane with an extremely long vertical mast. Tower cranes are used in construction for large structures such as bridges and hi-rise buildings. |
| trolley |
The unit that travels on the bridge rails of a crane and carries the hoisting mechanism. |
| truck-mounted |
A type of mobile crane that is self-powered and mounted on a truck bed. The truck can be driven anywhere that a truck would normally go. |
| underwinding |
Winding rope from the bottom of the drum. Also known as bottom winding. |
| wheel-mounted |
A type of mobile crane that is mounted on a chassis, which may or may not be self-propelled. |
| winch |
A drum mounted on a frame with a motor on one end and gears on the other. Winches are often used as inexpensive alternatives to other lifting devices. |