Erector Set is the trade name of a toy construction set

Construction set

A construction set is a set of standardized pieces that allow for the construction of a variety of different models. The pieces avoid the lead time of manufacturing custom pieces, and of requiring special training or design time to construct complex systems...

 that is popular in the United States.
It consists of collections of small metal beams with regular holes for nut

Nut (hardware)

A nut is a type of hardware fastener with a threaded hole. Nuts are almost always used opposite a mating bolt to fasten a stack of parts together. The two partners are kept together by a combination of their threads' friction, a slight stretch of the bolt, and compression of the parts...

s, bolt

Screw

A screw, or bolt, is a type of fastener characterized by a helical ridge, known as an external thread or just thread, wrapped around a cylinder. Some screw threads are designed to mate with a complementary thread, known as an internal thread, often in the form of a nut or an object that has the...

s, screws, and mechanical parts such as pulley

Pulley

A pulley, also called a sheave or a drum, is a mechanism composed of a wheel on an axle or shaft that may have a groove between two flanges around its circumference. A rope, cable, belt, or chain usually runs over the wheel and inside the groove, if present...

s, gear

Gear

A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine....

s, and small electric motor

Electric motor

An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...

s.

The brand name is currently used for Meccano

Meccano

Meccano is a model construction system comprising re-usable metal strips, plates, angle girders, wheels, axles and gears, with nuts and bolts to connect the pieces. It enables the building of working models and mechanical devices....

 sets sold in the United States.
Patented in 1913, The Erector Set was invented by AC Gilbert

Alfred Carlton Gilbert

Alfred Carlton Gilbert was an American inventor, athlete, toy-maker and businessman. Born in Salem, Oregon and died in Boston, Massachusetts, Gilbert is best known as the inventor of the Erector Set.-Early life:...

 in 1911, and was manufactured by the A. C. Gilbert Company

A. C. Gilbert Company

The A. C. Gilbert Company was an American toy company, once one of the largest toy companies in the world. It is best known for introducing the Erector Set to the marketplace....

 at the Erector Square factory in New Haven, Connecticut

Connecticut

Connecticut is a state in the New England region of the northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, and the state of New York to the west and the south .Connecticut is named for the Connecticut River, the major U.S. river that approximately...

, from 1913 until its bankruptcy in 1967.