For many years chairs have been manufactured such that the seat or the back of the chair is made of an injection moulded plastics material.
Conventionally, in order to give these materials sufficient strength for relatively rugged use, there was provided a peripheral metal frame to which the seat or back could be connected. In this way, the chairs made were quite utilitarian but they remained somewhat expensive to manufacture and necessitated substantial assembly.
More recently it has been known to manufacture chair seats or backs from an unreinforced plastics material, with a plurality of ribs extending generally parallel to the centre line of the chair across a substantial portion of the depth or height of the seat or back, in order to provide the required strength.
These components, whilst having sufficient physical strength, are generally not very aesthetically pleasing and are often difficult and tiresome to clean and maintain.
It will be appreciated, that not only in outdoor chairs, but in those which are used commercially, there can often be a build up of dust and dirt. In order to clean the abovementioned types of chair it would be necessary for a cleaner to physically pass a cleaning cloth or the like along the length of each of the grooves.
Manufacturing of these chairs has also proved to be difficult, particularly in the moulding of the seat or back, as there are a number of relatively narrow ribs which need to be filled by the material being passed into the die during production.
It is common practice for chairs to be fitted with pivotal connections which are attached to the seats. The pivotal connection usually has a bias means so that when the seat is not being used it adopts a position directed generally upwardly so that no part of the seat extends substantially forward and, particularly with seats with arms, no part extends beyond the extension of the arms. This provides maximum space allowance for a person who is passing through an aisle of such seats. The bias usually takes the form of a counterweight which is generally connected to the rear of the seat on its underside.
Previous proposals have attempted to provide various modes of enabling movement of the seat about its pivot, and means of controlling such movement, however, these have been quite complex and necessitated substantial assembly operations.
Furthermore there have been provided various methods of connecting chairs to surfaces, say in stadium seating where there are a number of chairs connected to the concrete risers or the treads of the stadium arrangement, and it is desirable to permit this connection to be as simple and rapid as possible not only for initial setting up of the stadium, but also if there are damaged chairs which need to be removed so that they can be removed quickly and efficiently.
At the same time, the connection has to be sufficiently stable for a user to use the chair even under conditions of substantial excitement and without allowing a chair to be readily removed from the connection, as a chair so removed, can be used a weapon if there is any riotous behaviour.