US2353683A

US2353683A - Method of sharpening files

Info

Publication number: US2353683A
Application number: US500465A
Authority: US
Inventors: Martines Rene
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-08-30
Filing date: 1943-08-30
Publication date: 1944-07-18
Anticipated expiration: 1961-07-18

Description

July 18, 1944. I MARTlNEs 2,353,683

METHOD OF SHARPENING FILES Filed Aug. 30, 1943 min ATTORNEYS Patented July 18, 1944 UNITED STATES PATENT. ()F' F'ICE METHOD OF snARPENING FILES Rene Martines, Cranston, R. I. v Application August 1943, Serial No. 500,465

2 Claims.

This invention relates to a method and apparatus for the sharpening of files.

,File teeth are usually formed by a chisel cutting action which raises a tooth and provides an arcuate surface along the tooth adjacent its point. The teeth become dull by a wearing off of the point and some of arcuate surface. Files are sometimes attempted to be resharpened by etching or sandblasting but these methods are not entirely satisfactory as the original shape of the tooth is not restored.

One of the objects of this invention is to resharpen the file by restoring to each of the teeth the original shape that these teeth have when formed new by a chisel action.

Another object of this invention is to grind the worm arcuate surface adjacent the point of the tooth so as to cause this arcuate surface to run to a sharp point adjacent the surface with reference to which it is disposed at an angle.

Another object of this invention is to wipe abrasive material along this arcuate surface until this surface is worn back to the shape desired and a sharp point provided on the file tooth.

Another object of this invention is to wipe this v surface with a resilient element which will apply an abrasive cutting material thereto.

With these and other objects in view, the invention consists of certain novel features of construction, as will be more fully described and particularly pointed out in the appended claims.

In the accompanying drawing:

Fig. l is a sectional view illustrating the file resharpening apparatus and showing a file in po'- sition with reference thereto; I

Fig, 2 is a fragmental view showing in section and on a larger scale a portion of the cutting wheel and the file in its position with reference thereto;

Fig. 3 is a fragmental section illustrating similar to Fig. 2 but on a greatly enlarged scale;

Fig. 4 is a sectional view on substantially line 4--4 of Fig. 1;

Fig. 5 is a top plan view of the structure shown in Fig. 1 with parts broken away;

Fig. 6 is a diagrammatic illustration of a modified form of the invention.

In proceeding with this invention I provide resilient elements such as flexible wires for applying an abrasive cutting material to the teeth of a file.

' the drum '55.

elements I'B which may be conveniently supplied by attaching card clothing consisting of a fabric back ll to support these flexible elements 16 to The length and gage of the wire which is used will vary depending somewhat upon the size of the file which is to be ground. For example No. 35 wire is adequate for files with cuts from No. 1 to No, 6 while No. 31 wire is better for coarser files.

A sump i8 is provided below the drum [5 which sump contains oil and emery or a, suitable cutting compound designated generally IS. The flexible element or wires I6 dip into this cutting compound and become coated with the cutting compound lifting it upwardly to apply the compound to any surface with which it may come in contact.

A guard 20 extends from the rear of the stand Ii! arcuately forward as shown in Fig. 1 while a second guard 2i extends upwardly to cover the front side of the drum.

Upon the front side of the apparatus I provide a file supporting stand which consists of an arm 22 pivoted as at 23 to the forward supporting surface 24 while at the other end of this arm a post 25 is swivelly mounted as at 26 and supports a horizontal rod 2'! upon which a carrier 28 is mounted having a. plurality of rods 29 therein each equipped with a chuck 3!] for the holding of a file 3!. A spring 32 tends to swing the carrier 28 about the horizontal rod 21 as a pivot to cause the file 3| to move into engagement with the flexible elements l6 carried by the drum. The carrier 28 may be swung to and from the rotating drum by movement of the arm 22 along the arc having a radius 32 while the carriage may also be swung about the arc whose radius is 33 from the center of the post 25 which also pivotally mounts the carrier 28, Thus the position of the files with reference to the drum may be conveniently de-' termined.

The mill cut file 3! is formed by a chisel which provides a recess 35 (see Fig. 3) and at the same time forms the abrupt surface 31 and arcuate surface 38 while a secondary inclination 39 is also formed. The file teeth thus each designated generally 40 are provided with a sharp point 41 by reason of the junction of the

surfaces

31 and 38. It is this point which becomes worn to cause the file to become dull and it is desired to restore this point in resharpening the file which I accomplish with the apparatus heretofore described. The

file 3| is disposed substantially as shown in Fig. 1

wardly into the recess 35 so as to engage the next 7 tooth. As each of the elements wipe across the surface 38 they conform to the shape of the surface and wear back this surface so that the shape of the tooth by reason of this surface joining the surface 31 remains substantially the same or is resharpened to substantially the same shape as the tooth was prior to becoming dull. Thus the shape of, the tooth as it originally occurred is restored by the grinding back of this tooth along this long surface which forms the angle of the point of the tooth. y

It is not essential that the flexible element l5 extend from a rotary drum and I have illustrated in Fig. 6 these elements as mounted in a belttype 45 extending over the two pulleys or drums 46 while there is a supporting shelf '41 over which the belt 45 extends. By reason'of this elongated extent 48 above thisshelf 4'! a larger portion of a file lengthwise thereof may be sharpened at one time than where the sharpening occurs over a cylindrical portion having a short tangential extent engaged by the file.

After the files have been ground to restore the shape of their teeth so as to provide a sharp point the files may be pickled to further shape and also to give them the appearance of a new file where such is desired.

The flexibility of the elements I6 is such that files of various shapes may be resharpened, such for instance as flat, half-round or round, as well as dental burrs and the like. 1

I claim:

1. The method of sharpening a mill cut file comprising the steps of applying a rotary, wire bristled brush having abrasive upon the bristles thereof to the teeth of a file in such a manner that the abrasive bearing bristles travel in an arcuate path from the back of the teeth toward the cutting edges thereof thereby imparting an arcuate surface upon the back of the teeth and extending to the cutting edges thereof and thereby renewing the sharpness of the cutting edges.

2. The method of sharpening a mill cut file comprising the steps of applying a flexible bristled brush having abrasive upon the bristles thereof to the teeth of a file in such a manner that the abrasive bearing bristles are flexed and travel from the back of the teeth toward the cutting edges thereof thereby imparting an arcuate surface upon the back of the teeth and extending to the cutting edges thereof and thereby renewing the sharpness of the cutting edges.

RENE MAR'I'INES.