Self tapping stud

A self-tapping and/or self-carving stud having two or more right angle elongate grooves of alternate length in the tapered thread or projecting helical ribs. The right angled grooves enable tapping debris to accumulate in the grooves to help lock the threads for fastening the stud, particularly in irregular holes. The alternate length of the grooves helps make this stud design unbreakable, thus unbeatable for special situations especially in exhaust manifold applications.

FIELD OF THE INVENTION 
The present invention relates to a method and device for relatively simply 
replacing broken or installing new studs and, more particularly, to a new 
and improved self-tapping or self-carving stud like device. 
BACKGROUND OF THE INVENTION 
There are presently available so-called tap devices which are utilized in a 
pre-drilled hole of exact size to re-thread said hole. Typically, these 
prior art tap devices comprise an elongate bolt shape with a threaded 
portion that contains four spaced apart semicircular shaped cutouts each 
extending longitudinally the entire length of the threaded portion of the 
tap. 
Some major disadvantages of these prior art type tap devices are: (1) they 
have a single purpose, i.e., to tap or thread and exact sized pre-drilled 
hole; (2) exhibit a tendency to break as a result of, for example, the 
four elongate cutouts; (3) subject to becoming dull or weakened with 
repeated use; (4) tendency to effect cross threading when use in a 
pre-existing threaded boring; (5) generally not suitable for use in 
irregular or rough or mutilated or undersized pre-drilled borings; (6) the 
tapped boring requires thorough cleaning to remove debris so that a bolt 
or stud can then be inserted into the tapped boring requiring extra time 
and expense; and (7) self-tap threads do not always easily bite or grab 
and initiate themselves into unthreaded holes and instead of pulling 
themselves into a hole of some particular size or with some kind of 
irregularity they resist "start" tapping procedure so crucial to 
successfully tapping threads, again requiring extra installation time and 
expense. 
In contrast to the prior art, the present invention provides a dual 
function tap and stud device, enables multiple functions, is adapted for 
ease of use, substantially overcomes the disadvantages of the prior art 
noted above, generally enables quicker and improved thread cutting and may 
be used in some undersized boring holes. Some of the structural 
distinguishing feature of the present invention include a tapered tap 
thread portion, tap threads which are relatively sharp, two elongate "L" 
shaped grooves, two relatively shorter "L" shaped grooves extending a 
portion of the tapered tap portion and a threaded stud portion. 
SUMMARY OF THE INVENTION 
A dual function tap and stud device having particular utility for 
self-tapping or thread cutting a boring, for example, in a metal block and 
in particular the cast iron of an engine exhaust manifold, and for being 
utilized as a stud or bolt like part, comprising: 
an elongate shaft having a threaded tap member (11) and a stud or bolt 
member (12), said tap member having a plurality of tapered threads (22) 
and a plurality of uniform threads (34,35), the threads of said tap member 
have a relatively sharp or pointed edge or thread ridge (24-27), said tap 
member includes a pair of spaced apart generally diametrically disposed 
somewhat "L" shaped grooves (19,20) which have a length substantially 
equal to the length of said tap member (11) and having a pair of spaced 
apart generally diametrically disposed somewhat "L" shaped grooves (17,18) 
having a length substantially equal to or slightly greater than the length 
of the tapered portion (15) of said tap member, and a stud or bolt member 
(12) having a plurality of threads (39). 
OBJECTIVES 
Accordingly, it is an object of the present invention to provide a new and 
improved stud device. 
Another object of the present invention is to provide a new and improved 
tap device. 
Another object of the present invention is to provide a dual function tap 
and stud device. 
Another object of the present invention is to provide a tap device having a 
tapered tap thread. 
Another object of the present invention is to provide a tap device having 
relatively sharp thread edges. 
Another object of the present invention is to provide a tap device having a 
plurality of "L" shaped elongate grooves. 
Another object of the present invention is to provide a self-tapping stud. 
Another object of the present invention is to provide a thread cutting stud 
or self-carving stud. 
Another object of the present invention is to provide a self-tapping stud 
which can be used in rough holes or borings not perfectly round or 
straight. 
Another object of the present invention is to provide a self-tapping stud 
that can be used in undersized borings, with said self-tapping stud having 
tapered and sharp threads designed to enlarge the undersized boring and 
carve threads. 
Another object of the present invention is to provide a self-tapping stud 
that can be used in solid metals, relatively hard metals such as cast iron 
and some kinds of steel and the like. 
Another object of the present invention is to provide a self-tapping stud 
that can be inserted using a power tool such as an electric or pneumatic 
tool. 
Another object of the present invention is to provide a self-tapping stud 
designed to utilize tapping debris to enhance securing or locking of a 
portion of the self-tapping stud threads and/or shaft in the boring.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the drawings, there is shown a self-tapping stud 10 in 
accordance with the invention to have a robust configuration. 
Applicant has successfully operated the inventive self-tapping stud 10 
being formed from cold rolled steel with a heat treating of 0.015 case 
hardening, or other suitable material and hardness may be utilized. 
Self-tapping stud 10 comprises a tap portion 11, a stud or bolt portion 12, 
an intermediate shank portion 13 and a head portion 14. 
Tap portion 11 includes a tapered thread tip or end portion 15, a straight 
or none tapered thread portion 16, a first pair of diametrically disposed 
somewhat "L" shaped grooves 17 and 18, and a second pair of diametrically 
disposed somewhat "L" shaped grooves 19 and 20. The plurality of threads 
21 about end portion 15 are tapered and have relatively sharp thread edges 
22. Applicant has discovered that tapered and sharp threads 21 about 
portions of tap end or tip 15 effects or enhances alignment with any 
preexisting bore female threads (not shown) and thereby substantially 
prevents cross threading which is a frequent problem with use of a prior 
art tap (only) device (not shown). It should also be noted that, in 
accordance with the present invention, the relatively sharp thread edges 
22 (as compared to flat or dull edges of prior art tap devices) 
facilitates and enables self-tapping stud 10 to cut more easily and 
establish new female threads (not shown) as these pointed threads will 
first bite, grab and pull themselves better into a bore hole (not shown) 
which prior thereto did not have such female threads. In this regard it is 
believed by applicant that the "L" shaped grooves 17,18,19 and 20 
facilitate cutting of such female threads by the presentation of pointed 
cutting edges or thread tips 24,25,26 and 27 at the ends of the threads 
defining, in part, the bottom ledges 28,29,30 and 31 of grooves 17,18,19 
and 20, respectively. 
Tap portion 11 also includes a plurality of thread sections 32 and 33 
having a plurality of sharp-edged threads 34 and 35, respectively, which 
define a circumference or thread diameter 36 approximately equal to or 
less than the diameter of intermediate shank portion 13. Accordingly, 
thread sections 32 and 33 and threads 34 and 35 are not tapered to define 
threads adapted for being mating received by female threads (not shown) 
within a bore hole, for example, in an automobile engine block or the 
like. 
It should also be noted that tap portion with its tapered and non-tapered 
sharp and pointed thread edges 24-27 may be utilized to cut the boring 
wall to create the desired mating female threads therein. 
The first pair of grooves 17 and 18 each longitudinally extend from tip 9 
rearwards along a partial portion of tap portion 11. The length 37 of 
grooves 17 and 18 are approximately equal to or slightly longer than the 
length of tapered portion 15. It should also be recognized that grooves 17 
and 18 may extend from tip 9 rearwards into a portion, for example, the 
first or second or several threads of the non-tapered thread sections 32 
and 33 of tap section 16. Some purposes of partially extending grooves 17 
and 18 along tap section 11 are VIS: to improve tap section 16 strength 
relative to prior art tap devices and to retain substantial thread 32 and 
33 surfaces for engaging the boring female threads. 
Said first pair of grooves 17 and 18 each have a length approximately equal 
to or greater than the length of the tapered end portion 15. 
The second pair of grooves 19 and 20 extend generally from tip 9 rearwards 
approximately to or within a portion of intermediate shank portion 13. 
Said second pair of grooves 19 and 20 each have a length approximately 
equal to or greater than the length of the tap member 11. 
In this manner, a multi-purpose and multi-function self-tapping and/or self 
thread cutting, and stud-bolt member 11 is provided. 
Stud end 14 contains a plurality of flat surfaces 40 dimensioned for being 
engaged by, for example, a wrench or power adaptor or socket wrench or the 
like to enable stud 10, i.e., tap/bolt section 11 to be driven into a bore 
hole in a metallic block or piece of metal etc. 
In this manner, a dual function improved tap and stud is provided to 
obviate the need to first tap a hole using a discrete conventional tap 
device and next inserting a discrete stud device. 
With reference now to FIG. 6, a cutaway perspective view of alternative 
embodiment of the self-tapping stud according to the present invention is 
shown. The self-tapping stud 45 is similar to the stud 10 shown in FIGS. 
1-5, with the exception that a somewhat pointed end 46 and a plurality of 
blades or contoured/sloped tip surfaces 47 are provided at or project from 
the tip of stud 45. Pointed end 46 and blades 47 are integrally formed 
with stud 45. This alternative tip, referred to as debris removing 
antisnag tip, section 50 has been found to facilitate insertion and 
installation of stud 45 into an irregular shaped and/or a very dirty or 
debris filled bore hole (not shown) into which stud 45 is inserted and 
rotated. This tip design is intended to prevent resistance in such 
installation, just mentioned which otherwise could result in improper 
installation, damage or breakage of either or both stud or metal block 
component to which installation is being made. This design is more 
effective, durable and resistant to breakage during installation, than the 
prior art. 
OPERATION 
The general operation of self-tapping stud 10 (or 45) will now be discussed 
with reference to the drawings. 
Let it be assumed that either an appropriately sized bore hole already 
exists or is drilled in a metal block which must be tapped to define 
suitable female threads. 
The tapered tap end 15 is urged into the bore hole and stud 10 is rotated 
clockwise. As each tapered thread 21 engages an existing female bore hole 
thread, stud 10 threads are aligned therewith. This is facilitated due to 
the relatively sharp tap thread edges 22 which juxtaposition the threads 
of stud 10 between any existing female thread. It being recognized that 
the threads along tap section 11 are relatively sharp. 
If the bore hole is slightly undersized, the tapered section 15 of tap 
member 11 provides increasing diameters cutting thread-teeth to cut a 
female thread within the undersized boring. Thus, each thread of larger 
diameter and, more particularly, each edge 24-27 of each section of 
tapered threads defined by grooves 17-20, cut deeper into the side wall of 
the boring until female threads are defined about the boring to 
accommodate the bolt like non-tapered threads along tap section 16. 
As the thread tapping or cutting operation progresses, an amount of metal 
etc. debris is caused to develop. Applicant has discovered that in 
particular the shorter grooves 17,18 also serve the purpose of providing a 
space or pocket into which this debris is stored/deposited during the 
tapping/cutting action of self-tapping stud 10. In this manner, the 
present invention not only attempts to eliminate the need for cleaning a 
bore hole prior to inserting a new stud, but combines the operation of 
tapping and inserting a stud 10 into one single operation. 
With reference to FIG. 6, the alternative self-tapping stud 45 with its 
pointed end 46 and blades 47 may be used in a bore hole having irregular 
contour or shape such as a mutilated hole or otherwise one having a 
substantial amount of debris therewith. The pointed tip 46 and blades 47 
were discovered to facilitate and enable insertion of stud 45 without 
first cleaning the bore hole of such debris or irregularity. 
While there has been shown what is considered to be the preferred 
embodiments of the invention, it is desired to secure in the appended 
claims all modifications as fall within the spirit and scope of the 
invention. For example, it is possible to substitute cold rolled steel 
with high speed steel and a different case hardening to better suit a 
special situation or application for installing self-tapping stud into a 
harder material etc., another modification could include the length of 
tapered portion 15 to be longer or shorter depending upon usage, 
thickness, or hardness of material etc.