US1673874A - Method of finishing lasts - Google Patents

Description

June 19, 1928. 1,673,874

P. S. JONES -METHOD OF FINISHING LASTS Filed Aug. 6, 1924 at least Patented June 19, 1928.

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PAUL S. JONES, BROCKTON, MASSACHUSETTS.

METHOD OF ,F SH N mews- Application filed August 6, 1924. Serial No. 730,483.

My present invention relates to lasts, and more particularly to an improved method of finishing lasts. I

In the manufacture of lasts as practiced at the present day, an important and costly operation is 'theoperation of scouring The scouring operation takes place intermediate the turning operation and the sandpapering operation. The .last, as it comes from the lathe, is covered with tool marks which cause a series of ridges over the surface of the last and it is necessary that these ridgesbe'removed before the operation of sandpaperingean take place. At thepresout day, thisremoval of the tool marks, known as scouring, is performed by holding the last against an abrasive wheel which scours off the tool marks. As'the last is necessarily held in the hands of the operator and as the securing wheel rapidly removes the surface of the last, there is great danger of the shape of the last being destroyed or badly injured due to the operator holding any portion of'thelast against the abrasive wheel for too long a period. Various attempts havebeen made to obviate the necessity of the scouring process, none of which has been successful and no means of which I am aware have been devised for performing the operation so as to remove the danger of injury to the last. j

n my present invention I have devised an improved method of finishing lasts whereby the scouring operation is dispensed with and the tool marks removed from the last prior to the sandpapering operation and this improved method of operation obviates the objectionable features of prior methods and further prevents injury to the shape of the last.

In practicing my improved method I employ a mass of metal such as a special form of fiatiron heated by gas, or preferably by electricity, and by moving said heated iron over the surface of the last the ridges caused by the forming tool in the lathe may be removed, the bottom of the troughs between adjacent ridges acting as a template or indicator for determiningthe length of time the iron is to be applied. During the burning oil of the surface of the wood constituting the ridges of the tool marks, the wood becomes charred or blackened so that the extreme lower portion of the trough between adjacent tool marks shows up as a white line which gradually becomes narfinally obliterated. This great advantage over prior rower until it is point is of methods employed in the scouring operation as, duringthe scouring, the hollow between adjacent ridges became wood and there was thus left on the surface of the last no distinguishing feature that could act as a guide to the'operator. I find that, in practicing my improved method, the joining line betweenthe upper portion of the last and the sole portion may be made as sharp as desired and there is no danger of ruining such joining edge as exists when prior methods are employed.

In practicing this improved method, the last maybe held in thehand of the operator and moved into engagement with the stationary heated iron or thelast may be held stationary and 'a' movable iron held by the operator maybe moved over the surface of the last or I may, if I so desire, place the iron or heating element a lathe and holidtl ie same against the surface of the last, the last being turned as would be the case in the preliminary forming operation.

In the accompanying drawing illustrating the various steps of my invention,

Fig l is a side elevation of a last as itcomes from the turning lathe,

Fig. 2 is afragmentary portion of the last shown in Figl, and with the heating element being applied thereto;-

F ig. 3 shows a view similar to Fig. 1 but at a further advanced manner in which the bottom of the cuts are utilized as a depth gauge, and

Fig. 4 is a view of the completed last prior to the sandpapering operation and illustrating how the shape of the last is accurately maintained.

Referring to the drawings, 10 designates a last after the turning pleted, such last -being rotatably mounted on the live and dead centers 11 and 12 respectively of the turning lathe (not shown). As indicated in Figs. 1 and 2, the width of cut on the last is responsible for the plurality of substantially parallelly arranged grooves 13 and which grooves heretofore have been removed by the ordinary scouring operation. In practicing my present invention, however,

utilize a heating element 14 in which the heat is maintained either by the use of gas or electricity and which, when held against the last, as shown in Fig. -2, will result in stage and indicating the a filled with powdered V in a tool holder in the high portions between the bottom of adjacent grooves being charred away, as indicated at 15 in Fig. As the charred wood becomes discolored, the bottom of the grooves retaining their natural color, will gradually deiine an e\er decreasing width ol? line it which will serve as an indicator to the operator as to the accuracy of the charring or finishing operation. Line 16 being; in direct contrast to the darkened charred portion to gradually becomes narrower as the charring operation proceeds, until eventually it will be practically obliterated. Atthis particular point, the last will have assumed the appearance shown in Fig. 4.

It is obvious that an operator, by utilizing the contrast between the charred portion 15 and the bottom of the grooves 13. as indicated by the ever decreasing width of line 16. will be able to accurately carry out the operation and will be able to produce a. last which will be true as to shape and size, and as all lasts cut on a machine are of a, certain size and shape, the present invention insures that lasts turned out from the factory will be accurate, as far as size and shape are concerned, and also all lasts of a certain size will be exact; duplicates of each other. This is not possible with prior methods of procedure, as during the scouring operation, and as above pointed out, there is no contrast between the portion scoured oil and the unscoured portion, and further, the depressions formed by the cutting tool gradually become tilled with the wood-dust scoured off and the operator has no method or no means of determining when he has reached the bottom of the cut. The resulting consequence is that from a practical standpoint no two lasts 01 presumably the same size and shape are identical.

As I am informed that. my present method of finishing lasts by removing with a hot member the tool marks :aused during the turning operation is new, I desire to claim the same broadly herein. Further, I am not to be limited in practicing my improved method to a movable heating element or a stationary heating element and l may, without departing, from the spirit of my invention, employ either form of heating element indiscriminately.

Having thus described my invention, what I claim as new is:

That improved method of finishing lasts which consists in taking the last as it comes from the turning lathe, and with the ridges caused by the cutting tool still thereon, bringing a heating tool into engagement with the lasts to remove the ridges caused by the cutting tool and utilizing; the trough between adjacent ridges as an indicator to determine the amount of material to be removed by the heating eleiuent.

In testimony whereof, I have signed my name to this specification.

PAUL S. JONES.

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