Machine suitable for operating progressively along marginal portions of shoe bottoms

A computer-controlled machine for progressively roughing marginal portions of shoe bottoms comprises a tool carrier on which two rotary roughing brushes (168) are carried side-by-side, and a shoe support (18) between which and the tool carrier relative movement takes place lengthwise, widthwise and heightwise of the shoe bottom. Each tool (168) is mounted so as to "float" heightwise in relation to the tool carrier, resilient means (175) being provided for urging each tool independently downwardly towards the shoe support (18). In this way the pressure applied by each tool to the shoe bottom in the operation of the machine can be controlled and/or regulated. For effecting relative movement between tool carrier and shoe support, numerically controlled motors are provided, operating in response to a programmed instruction. Such instruction can be made using the machine in a path-determining mode. The machine also comprises sensing means for sensing a defined heightwise position of the tool (168) in the path-determining mode of the machine, and the co-ordinate axis values for each selected position of tool carrier and shoe support are digitised, for each point, in relation to such defined heightwise position of the tool relative to the tool carrier. Similarly, the tool is maintained in a defined heightwise position in relation to the tool carrier during any brush grinding operation.