4.1 Crane Types & Working Parts by Restriction: Lattice, Derrick, Tower, Telescopic & Hydraulic Machines
Key Takeaways
OPSI bases the hoisting exam on thorough and practical knowledge of all working parts of the machinery in the restriction applied for, plus safe operating practices, inspection, hand signals and Massachusetts law.
Lattice boom, friction clutch, derrick and tower crane components (gantry, pendants, boom hoist, master clutch, dogs and pawls) belong to the 1A restriction.
A telescopic crane that lifts on a wire rope hoist line (1B) has outriggers, a swing bearing, telescoping boom sections, a boom lift cylinder, hoist winches and a hook block or overhaul ball.
OSHA 29 CFR 1926.1433(d) requires load hooks, overhaul balls and blocks heavy enough to overhaul the line, marked with rated capacity and weight, and latched unless a qualified person decides otherwise.
Assembly and disassembly follow the manufacturer's specifications under an A/D director, and employees must not be under the boom while pins are removed (230 CMR 6.09(1)(g); OSHA 1926.1404).
Why working parts are on the exam
The OPSI application states the exam "is based on thorough and practical knowledge of all working parts of the hoisting machinery that the applicant is applying for." A 1B candidate should expect questions about telescopic crane parts, and a 1A candidate about lattice, friction and derrick parts. OSHA also requires operators to know the controls, functions, safety devices and operational aids of their equipment (29 CFR 1926.1427). The manufacturer's operator's manual, which 230 CMR 6.08(2)(c)15 requires to be in the machine, is the authority for any specific model.
Lattice boom cranes and friction machines (1A)
A lattice boom crane may be mounted on crawlers or a truck carrier. Its main parts:
| Component | Function |
|---|---|
| Carbody and crawler side frames (crawler) / carrier (truck) | Lower works that carry the machine and form the tipping fulcrum |
| Revolving upper works with swing bearing or turntable | Carries engine, drums, cab and counterweight; rotates on the swing circle |
| Counterweight | Balances the boom and load. OSHA 1926.1417(aa) forbids operating without the manufacturer's specified counterweight or with more than the maximum |
| Gantry (A-frame) | Raised frame that carries the boom hoist reeving |
| Boom hoist and boom hoist reeving | Drum and wire rope that raise and lower the boom through the bridle |
| Pendants | Fixed-length standing wire ropes (or bars) from the bridle to the boom tip |
| Boom sections: butt, inserts, tip | Pinned lattice sections of chords and lacings; boom length depends on the inserts used |
| Jib (fixed or luffing) | Extension on the boom tip, usually lifting on the auxiliary line |
| Boom stops | Keep the boom from going over backward; cable stops alone are not adequate (230 CMR 6.09(1)(b)) |
| Main and auxiliary (whip) hoist drums | Wind the load lines; the whip line usually runs over a rooster sheave or jib tip |
| Friction clutches and band brakes | On mechanical "friction" machines, transmit power to the drums and hold them; inspected daily under 230 CMR 6.08(2)(b) |
| Drum pawls and dogs | Mechanical locks on drums or swing; the "Dog Everything" hand signal tells the operator to set them |
| Master clutch | Engages engine power to the drive train; the operator must not leave the machine while it is engaged (230 CMR 6.09(1)(f)) |
Free fall. Some older friction machines can lower the boom or load in free fall. OSHA 1926.1426 forbids boom free fall when anyone is in the fall zone, when personnel are hoisted, or near power lines, and forbids load-line free fall when anyone is directly under the load. Personnel hoisting requires powered, controlled lowering (Section 10.2).
Derricks and tower cranes (1A)
| Machine | Recognizing features |
|---|---|
| Guy derrick | A vertical mast held by guy lines, with a boom pivoted at the mast foot |
| Stiffleg derrick | A mast braced by two rigid stifflegs fixed to sills |
| Chicago boom | A boom mounted on a building column or structure, using the structure as the mast |
| Gin pole | A single guyed pole with tackle at the top |
| Tower crane | A tower (mast) with a slewing unit, jib, counter-jib with counterweight, trolley and hook; tied into the structure as needed; foundation designed by the manufacturer or a registered professional engineer (230 CMR 6.09(1)(j)) |
Derricks need a daily check of guys, cable clamps and rigging (230 CMR 6.09(2)). Tower cranes must have all required safety devices and operational aids working, or approved temporary alternatives (230 CMR 6.09(1)(l)–(m)). When out of service, they are normally left free to weathervane under the manufacturer's instructions (Section 7.3). Tower cranes are also the one exception to the rule against working under a suspended load (230 CMR 6.08(2)(c)14).
Telescopic cranes with wire rope (1B)
The truck crane, rough-terrain crane, all-terrain crane, carry-deck crane and boom truck that lift on a winch and wire rope share these parts:
| Component | Function and inspection points |
|---|---|
| Carrier and outriggers (beams, jacks, floats) | Support the crane. Jacks have integral holding devices or check valves (OSHA 1926.1415(a)(5)), beams extend to the positions the chart requires, and the crane is set on adequate blocking (230 CMR 6.08(2)(c)17) |
| Turntable / swing bearing and swing drive | Large bolted bearing carrying the upper; swing brake and lock |
| Boom base and telescoping sections | Extended by telescope cylinders (and on some cranes cables or chains) sliding on wear pads |
| Boom lift (elevation) cylinder | Hydraulic cylinder that sets the boom angle, with holding (counterbalance) valves |
| Main and auxiliary hoist winches | Hydraulic motors and drums with spring-applied brakes; line pull is limited by layer and parts of line (Section 5.2) |
| Boom head sheaves; optional swing-away jib or extension | Carry the load line; a jib has its own chart and deductions (Section 4.3) |
| Hook block / overhaul ball | Multi-sheave block for several parts of line; ball for single-line work. Must be heavy enough to overhaul the line, and marked with rated capacity and weight (OSHA 1926.1433(d)(2)–(3)) |
| Hook latch | Required unless a qualified person decides latchless hoisting is safer and routes keep workers out of the fall zone (1926.1433(d)(4)) |
Hydraulic hoisting equipment without wire rope (1C)
1C covers hydraulic telescoping booms and other hydraulic hoisting equipment that do not have wire rope hoist lines. Examples include rough-terrain telehandlers and other hydraulic machines that lift with forks or a hook mounted directly on the boom. With no winch, there is no line pull or reeving limit. The load chart, the load-moment or stability system, leveling (frame sway) and attachment ratings become the critical limits. A telehandler fitted with a winch and wire rope has a telescoping boom and wire rope, the 1B description.
Safety devices and operational aids at a glance
OSHA separates safety devices (29 CFR 1926.1415) from operational aids (1926.1416):
| Safety devices: no operation without them | Operational aids: temporary alternatives allowed while repairs are made |
|---|---|
| Crane level indicator; boom stops (except derricks and hydraulic booms); jib stops; foot pedal brake locks; hydraulic outrigger and stabilizer holding devices; rail clamps and stops; horn | Category I (7 days): boom hoist limiting device, luffing jib limiting device, anti-two-block device. Category II (30 days): boom angle or radius indicator, jib angle indicator, boom length indicator, load weighing or load moment indicator, outrigger position sensor, drum rotation indicator |
Inspection and repair deadlines are covered in Section 9.2.
Assembly and disassembly
- 230 CMR 6.09(1)(g): erection or dismantling follows the manufacturer's specifications and 29 CFR 1926, supervised by the manufacturer's representative or others experienced with that equipment. Attachments must not exceed the manufacturer's capacity, rating or scope.
- OSHA 1926.1403–1404: follow manufacturer procedures (or employer procedures that meet 1926.1406). The work is directed by an A/D director, a person who is both competent and qualified, or a competent person assisted by qualified persons. The A/D director reviews the procedures, briefs the crew on tasks, hazards and positions to avoid, addresses ground conditions and blocking, and makes sure rated capacities are not exceeded during any phase.
- Pins: while pins (or similar devices) are being removed, employees must not be under the boom, jib or other components. The only exception is where site constraints require it, in which case the A/D director implements procedures to minimize the risk and the exposure.
- Power lines: no part of a crane being assembled may be below a power line unless the line is de-energized and visibly grounded, and none may come within the Table A distance (1926.1407).
- After assembly: a qualified person inspects the crane to confirm it is configured to the manufacturer's criteria before use (1926.1412(c)).
- Capacity aids during A/D: this is the only time 230 CMR 6.08(2)(c)4 allows use of the load moment indicator override key.
On a mechanical friction crane, which component does 230 CMR 6.09(1)(f) say must not be engaged when the operator leaves the machine?
The swing brake
The master clutch
The boom stop
The anti-two-block switch
Under OSHA 29 CFR 1926.1433(d), which requirement applies to load hooks, overhaul balls and load blocks?
They must be painted to match the crane manufacturer's color code
They must weigh at least 10% of the crane's rated capacity
They must be heavy enough to overhaul the line and be marked with their rated capacity and weight
They may be used without latches whenever the operator prefers
During disassembly of a lattice boom, what does OSHA 29 CFR 1926.1404 require while boom pins are being removed?
Employees must not be under the boom, jib or other components, except under A/D-director procedures where site constraints require it
The operator must keep the load moment indicator in override
At least two workers must stand under each boom section to steady it
Pins may be removed only after the crane's annual inspection
Sections you finish are checked off in the contents.