Rim mechanism for tire inspection arrangement

In a tire inspection arrangement which includes a rim mechanism having an upper rim mechanism rotatably supporting an upper rim and a lower rim mechanism also rotatably supporting a lower rim for vertical movement with respect to said upper rim for inspecting a tire fitted between said upper and lower rims, the improvement of said rim mechanism which comprises stopper members movably provided in a reduced diameter portion of said upper rim so as to be selectively projected radially outwardly from and retracted radially inwardly into said reduced diameter portion, a central shaft axially extending through said upper rim and coupled thereto for vertical movement and simultaneous rotation in one unit with respect to said upper rim by driving means, cam means provided at the lower end portion of said central shaft for said selective projection and retraction of said stopper members from and into said reduced diameter portion in association with the vertical movement of said central shaft, a support shaft axially extending through said lower rim having a hollow cylindrical portion to be fitted into said reduced diameter portion of said upper rim, for vertically moving said lower rim with respect to said upper rim and also rotating said lower rim through a predetermined angle with respect to said upper rim by driving means, and lower engaging stepped portions to be stopped by said stopper members so as to set the lower rim at a position for defining a predetermined rim width with respect to said upper rim and upper engaging stepped portions to be stopped by said stopper members so as to set the lower rim at another position for defining a rim width slightly broader than said predetermined rim width with respect to said upper rim, said lower and upper engaging stepped portions being respectively provided on the hollow cylindrical portion of said lower rim in positions of displacement in the direction of rotation of said lower rim, said stopper members being displaced by the rotation of said support shaft for changing over of the engaging positions thereof between the lower engaging stepped portions and the upper engaging stepped portions.