Castors for chairs and other articles of furniture

Claim 1

In combination a chair having a base, and a plurality of castors supporting the base from a supporting surface, each castor comprising a housing, a wheel rotatably mounted in said housing for rotation about a substantially horizontal axis means mounting said housing on said base for pivotal movement relative thereto about a substantially vertical axis spaced from the said horizontal axis on one side thereof, and abutment means rigid with said housing and spaced from the vertical axis on the other side of the horizontal axis, said abutment means having a straight end edge extending parallel to the said horizontal axis and lateral edges extending transversely to the end edge, the end edge and the lateral edges lying in an imaginary plane below the said horizontal axis, when the chair is occupied and each said castor is in contact with supporting surface, the abutment means being spaced from the supporting surface with the said plane being inclined to the supporting surface, and when the chair is tilted whereby at least one castor is raised from the supporting surface, the abutment means of other castors contacts the supporting surface with the said imaginary plane of the abutment means lying in the plane of the supporting surface.