US2446848A

US2446848A - Punch

Info

Publication number: US2446848A
Application number: US712460A
Authority: US
Inventors: Prester Arthur
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-11-26
Filing date: 1946-11-26
Publication date: 1948-08-10
Anticipated expiration: 1965-08-10

Description

Aug. 10, 1948. PRESTER 2,446,848

PUNCH Filed Nov. 26, 1946 Im'eutor Army? Pmsiw Attoeys Patented Aug. 10, 1948 UNITED S TAT ES PATENT O F F I CE PUNCH iirthur Prester, Philadelphia, Pa.

Application November 26, 1946, Serial No. 712,460

1 Claim. 1

Tliisi'invention refers generally to punches, and more particularly to a small hand tool operated icy the manual compression of a spring, and sometimes referred to as an automatic punch because the use of a hand-held hammer is not required, the percussion member being a small internal hammer impelled by the spring against the pointed head of the punch.

An object of this invention is to provide such a tool which will be particularly well adapted for use as a center punch for use in laying out material preparatory to drilling, and for other like uses.

Another object of this invention is to provide an automatic punch which may be made with a light spring and a sharp, long tapered point adapting the tool for use as a prick punch, for such use as laying out templets in lofting.

Another object of this invention is to provide a tool of this type which is simplified in structure to a greater degree than currently used devices, these other devices being usually equipped with catches and other complicated structure frequently becoming inoperative.

A last object to be specifically mentioned is to provide such a tool in a form which is practicable and inexpensive to manufacture, simple and very convenient to use, and which is compact and sturdy and will give efficient and durable service.

With these and other objects in view as will appear hereinafter, this invention consists of certain novel features and construction, and combination and arrangement of parts as will be hereinafter described in detail and particularly set forth in the appended claim, reference being had to the accompanying drawings which form a material part of this application, and in which:

Figure 1 is a perspective view of the improved punch showing the retracted position of the stem handle in dash line and indicating the method of operation, to amplify this disclosure;

Figure 2 is a side elevation of this invention; and

Figure 3 is a vertical sectional view, taken on the line 3-3 in Figure 2, with portions being shown in elevation.

Similar characters of reference refer to similar or identical parts throughout the several views of the drawings.

Referring now to the drawings in detail, which drawings illustrate a preferred embodiment of this invention, it will be noted that the structure includes only four parts. The portion by which this tool is grasped by the hand is made in the form of a sleeve 10, which is interiorly threaded at the end i2, and at the other end thereof is provided with a cap M which is perfonatedlas at it. This perforated acap provides a bearing surface for the reciprocaitively mounted handlestem portion 18 of the hammer, the head portion 20 of which is of a diameter slightly less than the interior diameter of the sleeve ID. The terminal portion of the stem handle l8 may be knurled, as shown, better adapting this stem handle to be grasped by the fingers and withdrawn a short distance, compressing the helical spring 22 between the upper face of the hammer 20 and the inside of the cap I4.

This spring 22 encloses a major portion of the stem handle l8 and will be made considerably stronger when the device is to be used as a center punch than when the device is made in lighter form for use as a prick punch.

A pointed head 24, preferably of an exterior diameter equal to that of the sleeve 10, is provided with a projecting portion 26 which is exteriorly threaded to engage the threaded end l2 of the sleeve, and the end of this projection 26 is beveled so that a certain amount of peening or expansion of this part as a result of the percussive action of the hammer head 20 will not cause the threaded portion 26 to bind within the sleeve, making the pointed head 24 difiicult to remove. The lower edge of the head of the hammer is also beveled for the same reason and also to make the hammer more freely reciprocative within the sleeve.

Certain useful modifications of this illustrated embodiment of this invention will occur to machinists and loftsmen and others using the device, such as the mode of securing the pointed head 24 to the sleeve ID, the provision of an insert bearing in the apertured cap l4, and the provision of a stem handle in two parts, but it is contended that these and other like modifications are within the scope and spirit of this invention and within a proper interpretation of the claim hereunder appended.

In View of the foregoing disclosure of the structural details of this device, the method of operation thereof will be clear. When the device is to be used as a center punch, the angle of the pointed head 24 will be approximately 45 and the point will, of course, be hardened, the indentations in the work being made simply by placing the point at the desired position; retracting the hammer head 20 by withdrawing the stem handle H3 at short distance and allowing the same to snap back, striking the face of the beveled portion 28 of the pointed head 24. When the device is used as a prick punch, a more pointed head 24 and a lighter sprin 22 will normally be provided, but in the event that a center punch is adapted for use as a prick punch by merely sharpening the head 24, it will be necessary only to withdraw the stem handle [8 a very short distance, thus lessening the percussive force of the hammer 20. It is thought that other uses and adaptations of this device need not be detailed here, the above being adequately illustrative of the construction and method of operation of this invention.

Though there has been shown a particular embodiment of this invention, this application is not limited to this particular embodiment, but it is desired to include in the scope of this invention the construction, combination and arrangement of parts substantial-1y as set forth in the appended claim. 7

Having thus described this invention, what is claimed as new and desired to be secured by Letters Patent is:

A hand tool of the character described including a sleeve member, a pointed head secured to one end of said sleeve, a hammer reciprocatively mounted within said sleeve and having a 4 handle portion extending outside said sleeve, and a spring adapted to urge said hammer in one direction, said sleeve being threaded at one end thereof to engage a correspondingly threaded portion of said head and having a cap at the other end thereof, and said spring being of helical type and compressed between said hammer and said cap within said sleeve, said cap being perforated and integral with said sleeve and said handle having a stem extending within said helical spring and through said apertured cap and adapted to be pulled to compress said spring.

ARTHUR PRESTER.

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

UNITED STATES PATENTS Allen Dec. 17, 1940