US2492367A - Circumference and center point marker - Google Patents

Description

Dec. 27, 1949 I. N. OPRESCU 2,492,367

CIRCUMFERENCE AND CENTER POINT MARKER Filed May 24, 1946 FIG.|

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[/12 fl oreocur Patented Dec. 27, 1949 UNITED STATES PATENT 1 OFFICE CIRCUMFERENCE AND CENTER rom'r MARKER 1 Claim. 1

This invention relates to a center point cylindrical punch, and more particularly to such a device adapted for scribing circles and indicating the center points thereof in relation to bores of predetermined diameters.

A primary object of this invention is the provision of an improved device including a plurality of interchangeable cylindrical punches, each provided with a cutting edge and each adapted for a bore of a given diameter, each of which is provided with a centrally positioned aperture of identical diameter adapted to accommodate a center punch.

A further object of the invention is the provision of a tool of this character adapted to simplify the work of tool makers, machinists and others in accurately determining the outline diameter of and the exact center of circles to be drilled or otherwise machined.

Other objects of the invention will in part be obvious and in part be pointed out as the description of the invention proceeds, and shown in the accompanying drawings, wherein there is disclosed a preferred embodiment of this inventive concept.

In the drawings:

Figure 1 is a vertical sectional view taken substantially through the center line of one form of cylindrical punch embodying features of the instant invention'disclosing the center punch in association therewith.

Figure 2 is a view similar to Figure 1, but showing a different diameter of cylindrical punch and the center punch removed.

Figure 3 is a side elevational view of one form of cylindrical punch having the center punch associated therewith, shown in association with a piece of material to be marked through a bore of a diameter in conformity to the diameter of the cylindrical punch, the material in which the bore is formed being disclosed in section.

Similar reference characters refer to similar parts throughout the several views of the drawmgs.

Having reference now to Figure 1, there is generally indicated at H! a cylindrical punch of any desired diameter, the lower portion of which is recessed, as at H, the edges being beveled, as at l2, to provide a cutting edge l3 for scribing the exterior diameter of a circle of the exact size of the punch. The punch I is provided at its center with an accurately aligned bore [4 extending from the upper extremity thereof into the recessed portion ll, within which is adapted to fit an elongated center punch l5 provided with a point It adapted to extend a slight distance below the plane of the cutting edge I3. The upper extremity of the pin 15 carries an enlarged head I! of relatively heavy material, adapted to overlie the corresponding end of an associated cylindrical punch I0 and transmit the force of a hammer blow thereon to the cylindrical punch and center punch simultaneously.

Figure 2 discloses a similar cylindrical punch 10 provided with a recess ll' beveled, as at l2, to form a cutting edge I3, and being provided with an internal bore I4. It is to be noted that the punch II) is substantially identical to the punch In with the exception of its external diameter. The diameter of the internal bore [4' is substantially identical to the bore l4, and the length of punch III is substantially the same as that of punch I0 so that either the punch ID or the punch It will accommodate the center punch Obviously, numerous cylindrical punches similar to the above two described may be made in a variety of diameters, and are adapted to be accommodated in bores l8 formed in stock [9 of any suitable type, as disclosed in Figure 3, for the purpose of scribing circles with the edges [3 and marking the centers thereof with the point IS on any suitable material 20 to be worked.

From the foregoing the operation of the device should be readily understandable. When it is desired to mark and center a circle in any desired piece of material 28 through a bore It, a selected cylindrical punch In is first inserted in the bore, whereupon the center punch IS with its centering point It is inserted in the associated bore M to its full length, the point l6 extending a slight distance below the plane of the cutting edge l3. A relatively sharp blow with a hammer or similar device on the head i! will cause the cutting edge I3 to scribe the external diameter of the circle to be cut, and will simultaneously through the point It mark the exact center of the circle.

From the foregoing it will now be seen that there is herein provided a device which accomplishes all the objects of this invention, and others, including many advantages of great practical utility and commercial importance.

As many embodiments may be made of this inventive concept, and as many modifications may be made in the embodiment hereinbefore shown and described, it is to be understood that all matter herein is to be interpreted merely as illustrative and not in a limiting sense.

movably positioned in the bore o..-sa:id-' cy'lindnie cal punch and having a pointed end substantially in the plane of the cutting edge of said cylindrical punch end flange, and a head securedon the end of said center punch 01mm the pointed end thereof and overlying the corresponding end of said cylindrical punchvto transmit the force of a hammer blow on saidhead't'o 4 said cylindrical punch and said center punch simultaneously.

ILIE N. OPRESCU.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 306,413 McArdle Oct. 14, 1884 724,759 Twambley Apr. '7, 1903 '-72A3,-036v McA-lpine Apr. 21, 1903 766,677 Eagle Aug. 2, 1904 804,795 Cummings Nov. 14, 1905 824,867 I-Ioughton July 3, 1906 1395;081 Brion Oct. 25, 1921

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