Method and apparatus for making lasts

Claim 2

Method of manufacturing a shoe last made of a plurality of separable elements, including a standardized basic element and at least one interchangeable element dependent upon fashion, said method comprising the steps of marking the trace of the turning axis on the ends, and on each joint plane of the model elements and of the lasts deriving therefrom, and utilizing this trace for laying out means for interconnecting and positioning in proper relationship for interchangeable elements and the standardized element of the model and of the lasts deriving therefrom.

Claim 3

Method as set forth in claim 1, wherein the first interchangeable element is obtained by cutting the original model.

Claim 4

Method as set forth in claim 2, wherein the other interchangeable elements are obtained by modifying the first element.

Claim 5

Method as set forth in claim 2, wherein the other interchangeable elements are obtained separately by machining blanks drilled beforehand along the turning axis.

Claim 6

Method as set forth in claim 2, wherein the model is cut, while the same is rotatably driven about the turning axis, by means of a cutting tool of predetermined width, so that after a cylindrical bridge of material has been left between the two model elements coaxially to the turning axis, said cutting tool is replaced by a narrower tool fur cutting said bridge substantially across its median plane, whereby a cylindrical boss coaxial to the turning axis is left in the cutting plane of each one of the two elements for facilitating the detection of said axis.

Claim 7

Method as set forth in claim 2, wherein said cutting operation is accomplished on a last having dimensions slightly greater than those contemplated, the machining of said last being completed after the assembling of its component elements.

Claim 8

Method as set forth in claim 6, wherein for determining the position of the turning axis in the cutting plane of a last element, the guiding socket of a drilling tool is used, having a bore has the same diameter as said cylindrical boss, the latter being adapted to be fitted into said bore for drilling along said axis.

Claim 9

Method as set forth in claim 1, Wherein the blank utilized for turning the last element is associated with a compensating member corresponding to the missing element, the length of said member being adjustable very accurately.

Claim 10

Method as set forth in claim 1, wherein the model element utilized in the reproduction lathe is assembled with the complementary element of the same model.

Claim 11

Method as set forth in claim 1, wherein the model element utilized in the reproduction lathe is associated with a member for compensating the missing element and accurately adjustable in length.

Claim 12

Method as set forth in claim 7, wherein the hole drilled coaxially to the turning axis in the cutting plane of each element is utilized for positioning an assembling stud adapted to be locked in position by means of cross-pins.

Claim 13

Method as set forth in claim 11, wherein the transverse holes drilled in said last elements for receiving the assembling stud locking cross-pins are positioned on the end elements of the last with the assistance of the plane determined by the edge formed by the three points of the spindles of said reproduction lathe.

Claim 14

Method as set forth in claim 11, wherein the transverse holes drilled in said last elements for receiving the assembling stud locking cross-pins are positioned on the end elements of the last with the assistance of the reference marks reproduced on the turned elements.

Claim 15

Method as set forth in claim 11, wherein in the case of intermediate elements the holes drilled transversely for receiving the assembling stud locking cross-pins are positioned by means of reference marks made in proper regis-tration with the adjacent elements on the turned model, whereby said marks are reproduced on the turned elements.

Claim 16

Method as set forth in any of claim 11, wherein the transverse holes for positioning the transverse cross-pins of the interchangeable elements of the models or lasts turned from blanks are drilled in said blanks simultaneously with, or after, the holes made along the turning axis, that is, before the turning operation.

Claim 17

Apparatus for cutting shoe lasts or blanks into elements or sections, according to the method disclosed in claim 2, comprising on the one hand a circular saw having its shaft rotatably driven from suitable power means and journalled in bearings carried by a fixed frame structure and on the other hand a pair of bearings having a common axis parallel to that of said circular saw and said shaft, each bearing of said pair supporting a spindle for holding and rotatably driving about its turning axis a lathe model, means being provided for accurately adjusting the relative distance between the free ends of said spindles and also that of the bearings supporting said lathe model, other means being provided for permitting the simultaneous movement of the two lathe model supporting bearings in direction parallel and transverse, respectively, to the axis of rotation of said circular saw, further means being also provided for rotatably driving at least one of said spindles, complementary means permitting the relative angular position of said spindles.

Claim 18

Apparatus as set forth in claim 16, wherein said spindle bearings are interconnected by at least one rod rigid with one of them, the other bearing being adapted to slidde, or be locked in any desired position, along said rod, each bearing being mounted on a slideway extending at right angles to the axis of rotation of said circular saw, the pair of bearing slideways being mounted in turn on a frame structure adapted to slide along longitudinal slideways parallel to said axis of rotation of said circular saw.

Claim 19

Apparatus for drilling the end element of a multi-element model along the turning axis thereof, for carrying out the method set forth in claim 7 comprising on the one hand a fixed plate having fitted therethrough a socket having a bore corresponding in diameter to the cylindrical boss left on each joint plane of each model element, said socket being adapted to guide a twist drill for drilliNg the cavity engageable by the stud for assembling the model elements, and on the other hand a plate movable towards and away from said fixed plate, and supporting coaxially to said socket a three-point spindle identical with the spindle of the reproduction lathe, side plates provided with guide sockets perpendicular to the common axis of said first socket and said three-point spindle being disposed on either side of said fixed plate for drilling the holes for receiving the assembling stud locking cross-pins.

Claim 20

Compensation member for carrying out the method set forth in claim 8 comprising a rod of a length adjustable with precision, said rod being adapted to engage with one end the model element or to the last element blank, coaxially to the turning axis, and with the other end one of the spindles of said reproduction lathe.

Claim 21

Compensation member as set forth in claim 17, wherein its end adapted to engage the turned blank comprises a cylindrical end piece of same diameter as the cavity formed for receiving the assembling stud and provided with a transverse hole permitting the passage of the stud locking cross-pin.