Determining an operating path of a tool in relation to a three-dimensional surface of a workpiece

Claim 2

Method of determining an operating path of a tool in relation to a three-dimensional surface of a workpiece, the method comprising determining a plurality of points of contact between a tool and the surface of a workpiece and storing each such point, in the form of digitised co-ordinate axis values, in a memory device, from which set of co-ordinate axis values, corresponding to all the points, the operating path can be derived, the method being characterised in that, for determining each point, starting with the tool at a last preceding stored point on the surface of the workpiece, the tool is first separated from said surface, by a predetermined distance from said point, along a first dimension, whereafter the tool and said surface are returned into contact along said first dimension and/or along a second dimension and, in response to such return movement, corresponding relative movement takes place between the tool and surface simultaneously along a third dimension so as to maintain the predetermined distance between the tool and said last preceding stored point, the tool and surface thus being brought into contact at a further point, which is then stored as aforesaid, said further point, which is thus spaced from the last preceding stored point by the predetermined distance, regardless of the contour of said surface, thus constituting a next succeeding stored point.

Claim 3

A method according to Claim 1 wherein each point is spaced from its last preceding stored point by the same predetermined distance.

Claim 6

A method according to Claim 4 wherein the predetermined load is constant for all the points.

Claim 7

Apparatus for operating progressively along marginal portions of shoe bottoms, comprising a shoe support for supporting, bottom uppermost, a last carrying a shoe, tool supporting means, means for effecting relative movement, lengthwise, widthwise and heightwise of such shoe bottom, between the shoe support and the tool supporting means whereby a tool supported by the tool supporting means can be caused to move along an operating path relative to the bottom of a shoe supported by the shoe support, and means whereby said operating path can be determined in a setting- up mode of the apparatus, using a method according to any one of the preceding Claims, the apparatus being characterised in that said path determining means comprises - (i) actuating means whereby, starting from a first selected point of contact between the tool (168) and shoe bottom, relative heightwise movement is caused to take place between the shoe support (18) and the tool supporting means (26) through a predetermined distance, (ii) a manually operable control device (646) for causing relative heightwise and widthwise movement to take place between the shoe support (18) and the tool supporting means (26) under operator control, (iii) means, operable in response to relative movement being effected by operation of the manually operable control device (646), for causing relative lengthwise movement to take place between the shoe support (18) and the tool supporting means (26) simultaneously with such heightwise and/or widthwise relative movement so as to maintain the predetermined distance between the tool (168) and said first selected point, and (iv) computer control means, comprising (a) digitising means whereby a set of co-ordinate axis values can be calculated in respect of the relative positions of the shoe support (18) and tool supporting means (26) for each selected point of contact between tool (168) and shoe bottom, (b) a memory device whereby each such set of digitised values can be stored (the digitised values corresponding to all the selected points constituting a set of information from which the operating path can be derived), and (c) means whereby, when the apparatus is in an operating mode, the operating path of the tool (168) is derived from said set of information stored by said memory device.

Claim 8

Apparatus according to Claim 6 characterised in that operation of the digitising means is initiated under the control of the operator, the arrangement being such that, upon such initiation, the actuating means is also caused to operate' to cause relative heightwise movement to take place through a predetermined distance as aforesaid between the tool supporting means (26) and the shoe support (18).

Claim 9

Apparatus according to either one of Claims 6 and 7 characterised in that the means for effecting relative lengthwise, widthwise and heightwise movement between the tool supporting means and the shoe support as aforesaid comprises a plurality of numerically controlled motors (as herein defined) (144, 84, -).

Claim 10

Apparatus according to any one of Claims 6 to 8 wherein editing means (644) is provided by which corrections can be made to the digitised information, said means comprising another manually operable device (644) actuation of which causes the tool supporting means (26) and the shoe support (18) to be positioned at a desired digitised point to be corrected, the correction being made by said first-mentioned manually operable control device (646) as aforesaid, and the digitising means being actuated to calculate a set of digitised values for the corrected position, which set is then stored by the memory device in place of the information relating to the point before such correction.

Claim 11

Apparatus according to any one of Claims 6 to 9 wherein the tool supporting means supports a radial roughing tool (as hereinbefore defined) by which a marginal portion of a shoe bottom can be progressively roughed, and a scouring tool (320) is also provided by which a scouring operation can be effected on a toe end portion of the shoe bottom, the arrangement being such that relative movement, both lengthwise and heightwise of such shoe bottom, is effected between the scouring tool support (324) and the shoe support, the apparatus being characterised in that such relative movement is controlled by the computer control means in accordance with the set of information stored by .the memory device and using appropriate look-up tables.