US3029512A - Percussive type punch - Google Patents

Description

April 17, 1962 J. N. SAXTONPERCUSSIVE TYPE PUNCH 2 Sheets-Sheet 1 Filed April 4, 1960 INVENTOR, q/OHN IV- SAXTo/V;

ATTORNEY United States Patent 3,029,512 Patented Apr. 17, 1962 3,029,512 PERCUSSIVE TYPE PUNCH John N. Saxton, 4207 N. Harlan St., Baldwin Park, Calif. Filed Apr. 4, 1960, Ser. No. 19,669 1 Claim. (Cl. 30-367) The present invention relates to punches generally and specifically to a percussive type of punch. Punches are used for various purposes and the present invention has for an object a type of punch wherein the point may be pressed against work, the punch releasing at a given pressure to deliver a percussive blow against the point.

The particular punch is useful for various purposes such as an insert tool, a chiseiing tool and the making of indentations. The punch is particularly adaptable for layout work and for the locating of points on the layout.

A further object is the provision of a punch which is efiicient in operation, of few parts, inexpensive in cost of manufacture, and generally superior to punches of the character stated now known to the inventor.

With the above mentioned and other objects in view, the invention consists in the novel and useful provision, formation, construction, and association and relative arrangement of parts, members and features, all as shown in certain embodiments in the accompanying drawings, described generally and more particularly pointed out in the claims.

In the drawings:

FIGURE 1 is a vertical, sectional view of the punch as an entirety;

FIGURE 2 is a view similar to that of FIGURE 1, being in vertical section with certain parts shown in fragment, and in moved position;

FIGURE 3 is a vertical section similar to that of FIG-URE 2, certain parts being in further moved position from that of FIGURE 2;

FIGURE 4 is a vertical, sectional view, partly in fragment showing parts in moved position from that of FIGURE 3;

FIGURE 5 is a sectional view on the line 5-5 of FIGURE 1;

FIGURE 6 is a sectional view on the line 6-6 of FIGURE 1;

FIGURE 7 is a sectional view on the line 7-7 of FIGURE 1;

FIGURE 8 is a sectional view on the line 8-8 of FIGURE 3;

FIGURE 9 is a detached, fragmentary view of certain parts of the invention;

FIGURE 10 is an elevation of a chisel point which may be used in the practice of the invention; and

FIGURE 11 is a fragmentary sectional view of a point for punching holes in work.

Referring now to the drawings, and specifically to FIG- URE 1, the punch includes a tubular casing part 1 internally screw threaded at itsends 2 and 3, thethreads 2 engaging thethreads 4 of a cap or head 5 While thethreads 3 engagethreads 6 of astem retainer 7. This construction provides a housing or casing for the mechanism of the punch. This mechanism includes a stem orrod 8 axially bored inwardly from one end thereof and screw threaded at 9 with acounterbore 10 for the receiving of a point 11 which point has a screw threadedshank 12 for engagement with thethreads 9 and with an unthreaded reduceddiameter shank 13 for reception in thebore 10. I may substitute for the point 11 thechisel device 14 of FIGURE 10, or the hole forming device 15 of FIG- URE 11 provided with a side opening 16 through which severed slugs are directed. Both of the devices shown in FIGURES 10 and 11 are provided with threaded shanks and reduced diameter unthreaded portions for fitting within the threadedportion 9 of the stem orrod 8 and likewise within thebore 10. Other forms of devices may be incorporated and used with the stem orrod 8. The stem orrod 8 is passed through abore 17 in the lower end of thestem retainer 7, and the stem orrod 8 within the stem retainer is provided with ananvil 18. The anvil has a diameter closely approximating the diameter of an enlargedbore 19 in the stem retainer. Extending between thebores 17 and 19 is a conical wall 24) and theanvil 18 has alower wall 21 which is conical so as to rest, when in one position on thewall 26. The stem orrod 8 is axially bored at 22 the bore extending from theupper end 23 to azone 24, the bore terminating above theanvil 18. Further, the wall thickness of the stem orrod 8 for the area which includes thebore 22 varies from the lower end of the bore atzone 24 to anannular shoulder 25 whereupon the external diameter is reduced, as shown at 26 to theend 23 where the bore commences. Adapted to surround thestem 8 and specifically that portion included between the anvil and theshoulder 25, is ahammer 27 of annular form. 23 to form an annular shoulder at 29. interposed between the end of the cap or head 5 and the annular shoulder at 29 of the hammer, is acoil spring 30, this spring is termed the pressure spring as it is adapted to move the hammer against the anvil when the hammer is released. The blow of the hammer against the anvil is sudden, sharp, and strikes the anvil with considerable force as hereinafter set forth. 7

The cap or head 5 is provided with anaxial bore 31 and anannular bore 32 thus providing betweenbores 31 and 32 anannular wall 33. What I term arestoring coil spring 34 has an end portion received in thebore 32 and surrounds theannular wall 33 with the opposite end of thespring 34 resting upon awasher 35 which washer engages theannular shoulder 25. act upon the hammer but does bear against the stem or red 8.

Adapted for movement within thebore 22 of the stem or rod is a releasingrod 36. This rod has an uniform diameter and in the position shown for the rod in FIG- URE 1, the rod extends within thebore 31 of the cap or head 5. The lower end ofrod 36 is provided with a reduceddiameter stem 37. Theendof stem 37 is adapted to rest upon or engage theend 38 of aplunger release 39. The upper end of said plunger release is of conical form, as shown at 49, to provide a cam portion. Between the lower end of thebore 22, to wit:zone 24, and an end 41 p of theplunger release 39 is acoil spring 42 which con stantly urges the plunger release to the position shown in FIGURE 1. As stated, this plunger release is of cylindrical form and fits closely within thebore 22. The rod orstem 8 is provided with one or more, in the present instance three, equidistantly spaced aparttransverse bores 43 and in alignment with eachbore 43, for the position shown for the parts of FIGURE 1, the hammer is formed withsockets 44 adapted to house inpart balls 45. In this position, as shown in FIGURE 5, substantially one-half of each ball detent is within asocket 44 while the other half thereof is within abore 43. The plunger release in the position shown has its cylindrical wall surface engaging the detents to hold the detents within the sockets 4-4, which may be merged into a single annular groove, as in FIG. 5.

The cap or head 5 is formed with an axial screw threadedbore 46 opening inwardly from the top surface of said cap or head which communicates with a reduced diameterunthreaded counterbore 47. A screw threadedmember 48 engages thethreads 46 and said member has ashank 49 for passage through thecounterbore 47. The end of theshank 49 is for adjusting the axial movement of therelease rod 36 thereby governing the striking force of the hammer against the anvil.

This hammer is externally reduced in diameter at Thusspring 34 does not The operation, uses and advantages of my invention are as follows:

What I term the normal position for the punch is the position of the punch parts as shown in FIGURE 1, and wherein the conical bottom surface of the anvil is resting against the complementaryconical surface 20 of the stem retainer. Thespring 42 has moved theplunger release 39 to a position where theball detents 45 are held within thesockets 44 in the hammer. The point 11 is engaging the surface of work marked W. The operator grasps the casing, the palm of the hand engaging the top of the cap or head and pushes downwardly. Such action holds the stem orrod 3 against movement and as thehammer 27 is locked to the stem orrod 8 by theball detents 45, thepressure spring 30 is compressed to a certain extent and the restoringspring 34 is compressed between thewasher 35 and the cap or head 5. As the casing is moved downwardly from the position of FIGURE 2 to the position shown in FIGURE 3, the upper end of the releasingrod 36 is engaged by theshank 49, as shown in FIGURE 3 and as the casing is moved further downwardly, thepressure spring 30 is further compressed. Theplunger release 39 is moved downwardly by engagement therewith of the reduceddiameter stem 37 of therod 36. When this occurs, the ball detents are released from thesockets 44 in the hammer and moved inwardly of thebores 43 to release the hammer for striking engagement with the anvil as shown in FIGURE 4. The pressure spring causes the hammer to engage the anvil very suddenly and with considerable force with the result that the point 11 will indent the work W. Upon releasing pressure against the head or cap 5 of the casing as an entirety, the restoringspring 34 which is compressed in FIGURE 4 will move the casing 1 upwardly, and in so doing the parts will again assume the position shown in FIGURE 1 with the ball detents received in part within thesockets 44 of the hammer.

As previously mentioned, I may substitute other devices for the point 11 as shown on FIGURES l0 and 11 which is illustrative of certain applications of the punch. The cam surfacedupper end 40 of the plunger releases moves upwardly under pressure fromspring 42 to again cam the ball detents from the position of FIGURE 4 to that of FIGURE 1, and such camming action forces the ball detents into thesockets 44. If it is desired to regulate the striking pressure exerted by the hammer on the anvil, this may be done by adjusting themember 48 by moving it downwardly and thereby limiting the movement of the releasingrod 36. Obviously, a longer stroke or movement of the releasing rod will allow greater compression of the pressure spring with resultant greater pressure exerted against the hammer.

I claim:

A percussion punch of the type employing a cylindrical casing having slidable therein a spring pressed hammer for striking, when the casing is manually moved a chosen distance in its working stroke, an anvil having a hollow stern on one side and a penetrating tool on the other side, said casing having an annular shoulder normally holding the hammer spaced from the anvil, which shoulder is moved toward the tool when the casing is moved less than said chosen distance, and further movement of the casing toward the tool lowers the casing shoulder below the top of the anvil and simultaneously operates a release mechanism to free the hammer from the anvil stem to which it is temporarily secured, the casing having a contact member engaging the release mechanism as the casing is moved toward the tool: characterized by the contact member being adjustable from outside the casing, the hammer having axially through it a central bore in which is an internal socket groove normal to the axis of the casing, the anvil stem having a plurality of transverse bores, and the release mechanism comprising a release rod slidable within the hollow stem, a spring urging the anvil and its stem downwardly to normal position, said release rod being circular in transverse cross-section with a lower cylindrical section of lesser diameter, a release member slidable in the hollow stern, spring urging the release member upwardly into contact with the reduced lower end of the release rod, said release member having a camming surface at its upper end, a plurality of balls held at least partially within the transverse bores at all times, said balls being free of the internal socket groove in the hammer when in contact with said reduced end of the release rod and moved outward by said camming surface of the release member to engage the internal socket groove of the hammer and be so held by said release member, thereby to lock the hammer to the holow stem, manual movement of the casing to said chosen distance causing the adjustable contact member of the casing to engage the top of the release rod, thereby moving said release rod and the release member toward the tool, thus freeing the balls from the groove in the hammer, the diameter of the lower end of the release rod being suiliciently small to readily accommodate the balls and the lower end of the rod within the hollow of the anvil stem.

References Cited in the file of this patent UNITED STATES PATENTS 2,455,270 Ravella Nov. 30, 1948 2,787,178 Maxim Apr. 2, 1957 FOREIGN PATENTS 51,164 Sweden May 11, 1920

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