Chair

A chair is a piece of furniture with a raised surface commonly used to seat a single person. Chairs are supported most often by four legs and have a back; however, a chair can have three legs or could have a different shape. Chairs are made of a wide variety of materials, ranging from wood to metal to man made material, and they may be padded or upholstered, either just on the seat or on the entire chair (e.g., with a La-Z-Boy chair). Chairs are used in a number of rooms in homes (e.g., in living rooms, dining rooms and dens), in schools and offices (with desks) and in various other workplaces.

A chair without a back or arm rests is a stool, or when raised up, a bar stool. A chair with arms is an armchair and with upholstery, reclining action and a fold-out footrest, a recliner. A permanently fixed chair in a train or theater is a seat or, in an airplane, airline seat; when riding, it is a saddle and bicycle saddle, and for an automobile, a car seat or infant car seat. With wheels it is a wheelchair and when hung from above, a swing.

Chairman

The chairman or chairwoman, or simply the chair, sometimes known as chairperson, is the highest officer of an organized group such as a board, a committee, or a deliberative assembly. The person holding the office is typically elected or appointed by the members of the group. The chair presides over meetings of the assembled group and conducts its business in an orderly fashion. When the group is not in session, the officer's duties often include acting as its head, its representative to the outside world and its spokesperson. In some organizations, this position is also called president (or other title), in others, where a board appoints a president (or other title), the two different terms are used for distinctly different positions.

Terminology

Other terms sometimes used for the office and its holder include chair, chairperson, chairwoman, presiding officer, president, moderator, facilitator, and convenor. The chairman of a parliamentary chamber is often called the speaker.

The term chair is sometimes used in lieu of chairman, in response to criticisms that using chairman is sexist. It is commonly used today, and has been used as a substitute for chairman since the middle of the 17th century, with its earliest citation in the Oxford English Dictionary dated 1658-9, only four years after the first citation for chairman.

Rail fastening system

A rail fastening system is a means of fixing rails to railroad ties (United States) or sleepers (international). The terms rail anchors, tie plates, chairs and track fasteners are used to refer to parts or all of a rail fastening system. Various types of fastening have been used over the years.

History and overview

The earliest wooden rails were fixed to wooden sleepers by pegs through holes in the rail, or by nails. By the 18th century cast iron rails had come into use, and also had holes in the rail itself to allow them to be fixed to a support. 18th century developments such as the flanged rail and fish bellied rail also had holes in the rail itself; when stone block sleepers were used the nails were driven into a wooden block which had been inserted into a recess in the block. The first chair for a rail is thought to have been introduced in 1797 which attached to the rail on the vertical web via bolts.

By the 1820s the first shaped rolled rails had begun to be produced initially of a T shape which required a chair to hold them; the rails were held in position by iron wedges (which sometimes caused the rail to break when forced in) and later by wooden wedges, which became the standard. In the 1830s Robert L. Stevens invented the flanged 'tee' rail (actually a distorted I beam), which had a flat bottom and required no chair; a similar design was the contemporary bridge rail (of inverted U section with a bottom flange and laid on longitudinal sleepers); these rails were initially nailed directly to the sleeper.