DISPOSABLE ALIGNER FOR SELF-TAPPING THREADED INSERT

An aligner for use with threaded self tapping insert, a drive bolt, and a bushing, wherein said self tapping insert is driven into position in an accepting bore by said drive bolt passed through said bushing and through said self-tapping insert thread and fitted with said aligner, said aligner comprises a body, inscribed by a circle the diameter of which is slightly smaller than the diameter of said accepting bore; and an attachment means for attaching said aligner to said drive bolt, wherein said aligner aligns the central axis of said threaded self tapping insert with the central axis of said accepting bore when inserted therein.

FIELD OF THE INVENTION

The present invention generally relates to the field of threaded inserts, and more particularly, to a disposable aligner and a method for aligning the central axis of a self-tapping threaded insert with the central axis of its accepting bore, enabling accurate insertion of the self-tapping insert therein.

BACKGROUND OF THE INVENTION

Modern, well-equipped machine shops today are equipped with the needed technologies for dealing with machining, and restoring of threaded bores with attention to proper alignment of the bore in perpendicular to the work surface. A milling machine or drill press, for example, can be adjusted and used to re-bore a broken, rusted, or worn-out bolt thread by simply drilling an oversized bore perpendicular to the surface and then with the aid of the machine spindle, accurately applying a self-tapping, threaded insert with the correct inner thread to fit the original bolt. The outer self tapping thread of the insert is cutting a new, tight-fitting thread that is mechanically secure for tightening a bolt to the predetermined torque. By using a press drill the alignment is held to high tolerances and the need for a self-aligning tool, such as the aligner of the present invention, is minimal or non-existent.

But there are many situations where service must be provided in the location of the damaged part mostly in agricultural, transportation or industrial equipment. In such cases the use of machine shop equipment is impossible, inconvenient, inaccessible, or too costly and a machinist is called upon to use hand-tools, such as open-ended hexagonal-wrenches, box wrenches, electric-powered or manually driven, heavy-duty screwdrivers, drills, and the like for loosening, removing, reinstalling and tightening loose, broken, or damaged bolts in order to correct a problem. Proper alignment in such cases is of crucial importance in order to preserve the vertical alignment of the bolt with an existing threaded bore. Occasionally the axis of the self cutting insert may be considerably off the mark from the original axis, and the initial insertion may then result in a misaligned self tapping insert mounting as shown inFIG. 1(Prior Art).

There are, prior art attempts to solve the problem, such as U.S. Pat. No. 4,730,968 to Diperstein et al, which discloses a self-tapping and self-aligning thread repair insert configured with a thread-free portion of a sleeve that is fitted into a smooth bore to align the insert. The length of the thread-free portion seen in U.S. Pat. No. 4,730,968 is at least 1.5 thread pitches from the end of the sleeve. It will be understood to the person skilled in the art, that if this is the actual length, it is clearly insufficient for achieving an initial alignment within the accepting bore and therefore may lead to inaccurate insertion.

If an insert of greater length is employed, insertion of the insert requires extended boring depth to accommodate the added length of the thread-free portion. This may not always be possible since the wall thickness of a work piece may not be sufficient to allow for deeper boring. The thread-free portion itself also requires additional length of the insert.

US Patent Application 2010/0329813 to Strom teaches a self-tapping and self-aligning insert as generally described in the following abstract citation: “The self-tapping insert is aligned within the bore hole by means of a detachable pilot, which is connected to the insert with attachment means. The attachment means include the pilot being attached to the drive bolt. The pilot may be attached to the drive bolt by means of left-handed threads in an axially-centered aperture of the pilot and matching left-handed threads on the end of the drive bolt.”

A major disadvantage of this device is that the pilot needs to be threaded onto a special bolt with a small diameter, partially threaded, extension. Furthermore, using a machined steel pilot adds more labor and manufacturing costs to the finished product. Additionally, there is no solution to the tolerance of the accepting bore when using the pilot, a disadvantage which allows some degree of play in the alignment of the insert assembly and pilot.

The method of the prior art described by Strom requires partial insertion of the self-tapping insert for the first few turns, dismantling the insert itself with the drive bolt then dismantling the pilot and reinstalling the insert back into the few partially threaded pitches and continuing with the insertion of the insert assembly. This method creates the risk of cross-threading in the second step if the initial insertion was insufficient in depth, and the risk that the insert will stick and won't come out in the case of excessive initial insertion depth. Actually, self-tapping inserts should preferably not be slackened once properly inserted, to avoid weakening of the hold. However, Strom is constrained to extract and replace the self tapping insert as well as provide a threaded pilot with left handed threaded extension so as to be strong enough to enable extraction.

Therefore, it would be desirable to provide a method and a device for aligning a threaded self-tapping insert within an accepting bore utilizing standard drive bolt and hexagonal bush or larger nut.

SUMMARY OF THE INVENTION

Accordingly, it is a principal object of the present invention to overcome the disadvantages and limitations of prior art systems and provide a method and a device for inserting a self-tapping threaded insert into an accepting bore of a work piece so as to coaxially align the central axis of the insert with the central axis of the accepting bore when inserted therein.

According to one embodiment of the present invention, there is provided an aligner for use with threaded self tapping insert, a drive bolt, and a hexagonal bush, the self tapping insert is driven into position in an accepting bore by the drive bolt passed through the hexagonal bush and through the self-tapping insert thread and fitted with the aligner, wherein the aligner comprises:

at least three vertex polygonal body, inscribed by a circle the diameter of which is slightly smaller than that of the accepting bore; and

an attachment means for attaching the aligner to the drive bolt,

According to additional aspect, the above body is made of a semi rigid material and a plurality of wedge-shaped nibs arranged on at least three of said polygonal body vertexes are forming a snug fit when inserted into the accepting bore.

According to another aspect the polygonal body is replaced with a circular body and the wedge-shaped nibs are formed around the circumference of the face portion of said circular body.

According to a different embodiment, the above body is made of a thin resilient material in the shape of a circular shaft-retaining-ring, or of a rigid material in the shape of an internally threaded plain washer, or in the shape of a helical spring washer.

According to another aspect, the drive bolt when fitted with the self tapping insert for insertion into accepting bore is of a given length so as to expose an extended portion of the drive bolt beyond the self-tapping insert, attachable by the attachment means to the aligner.

According to yet another aspect, the attachment means comprises a collar centrally formed on the body of the aligner having an inside diameter suitable for attaching the extended portion of the drive bolt thereto in a temporary snap-fit attachment. Optionally, the collar forms a bore which is open to both directions and the bore end facing the workpiece direction is provided with a circular conical edge serving as a stopper.

According to still another aspect, the aligner further comprises an extension sleeve capable of being mounted over the drive bolt between the hexagonal bush and the self-tapping insert ensuring that the threaded end of the drive bolt is above cutting edges apertures leaving them open for burrs to be removed.

According to a second embodiment, the drive bolt comprises a central bore axially formed therein and an internal extension shaft slid-ably fitted into the central bore which is attachable to said aligner by attachment means to provide longitudinal support along the central axis of said insert at both an upper end of said extension shaft and at a lower end at the body of said aligner within said accepting bore. The attachment means comprises a central aperture formed within the aligner body having an inside diameter configured for temporary snap attachment to the extension shaft.

According to additional aspects, the above aligner body is made of a thin resilient material in the shape of a circular shaft-retaining-ring, or of a rigid material in the shape of an internally threaded plain washer, or in the shape of a helical spring washer.

As indicated above a method is provided for inserting a threaded self-tapping insert into an accepting bore of a work piece with the aid of a drive bolt, a hexagonal bush, an extension sleeve and an aligner as described above,

wherein the method comprises the steps of:

a) providing a drive bolt;

b) sliding the hexagonal bush over the drive bolt;

c) threading the threaded self-tapping insert on the drive bolt to the stop position;

d) attaching the aligner to the drive bolt exposed threaded end using the attachment means;

e) inserting the drive bolt with the hexagonal bush, threaded self-tapping insert and the aligner into the accepting bore;

f) rotating the drive bolt a few turns to insert a few threads of the self-tapping insert into the accepting bore;

g) Slackening the drive bolt with the aid of the hexagonal bush to leave the self tapping insert intact;

h) providing an extension sleeve;

I) repeating steps b to e with the extension sleeve placed between the hexagonal bush and the self tapping insert;

j) further rotating the drive bolt until the self-tapping insert is firmly seated within the accepting bore, flush with the surface of a work piece;

k) Slackening the drive bolt with the aid of the hexagonal bush to leave the self tapping insert intact,

wherein insertion of the drive bolt in step e together with the hexagonal bush, threaded self-tapping insert and aligner into the accepting bore utilizes an upper and lower alignment rest points coaxially aligning the central axes of the insert assembly with that of the accepting bore.

According to another aspect of the described method, in step h a shorter drive bolt is provided instead of an extension sleeve.

According to yet another aspect of the described method, the drive bolt is shorter, further provided with a central bore axially formed therein, fitted with an extension shaft longitudinally movable there-through and attachable to the aligner by the attachment means to provide longitudinal support along the central axis of the insert assembly at both an upper end of the extension shaft and at a lower end at the body of the aligner within the accepting bore and wherein method steps g to i are not needed.

Further features and advantages of the present invention will be apparent from the drawings and description contained herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the drawings, there is shown inFIG. 1, a side view of a self-tapping, insert26of the prior art which failed to align properly when initially inserted into a prepared accepting bore28in a work piece30. The self tapping insert26is shown with its drive bolt22and the bolt release hexagonal bush24as will be hereinafter explained.

The prior art self-tapping insert26is driven into the accepting bore28by a drive bolt22, and a thru-hole hexagonal bush24or hexagonal nut with internal thread bigger than that of the drive bolt22such that its thread is not engaged with the thread of the drive bolt22and it is free to rotate over the drive bolt22. The cutting edges of the self-tapping insert26are formed by the three apertures27(only one seen in this figure). The cutting edges cut a new thread into a smooth accepting bore28when properly inserted therein. However, the self-tapping feature shown here and generally used by way of example may be any kind of self-tapping insert as is known by those skilled in the art. For instance, a self-tapping insert may be provided with a number of slots forming the cutting edges.

When initially inserted and threaded into the smooth accepting bore28of a typical work piece30, the drive bolt central axis32, was incorrectly aligned with the accepting bore central axis34. When such a thing occurs, one side of the insert tips is less and less engaged with the wall of the accepting bore (as self-tapping insert26is inserted deeper) and the other side has to cut deeper into the wall until it sticks. Now it is very difficult to remove the self-tapping insert26for reinsertion. Furthermore, even if the self-tapping insert26is by chance partly aligned to the extent permitting it to be inserted all the way down, yet it will only aggravate the problem when, at a later stage, during assembly of the reconstructed device, a machine screw is threaded into the inner threads (not shown) of the partly aligned, self-tapping insert26.

FIGS. 2a-cshow various views of a disposable aligner36constructed in accordance with one embodiment of the present invention.

FIGS. 2d-fshow various views of a disposable aligner36aconstructed in accordance with a variation of embodiment of the present invention.

The aligners36,36aare constructed as at least three vertex polygonal body40inscribed by a circle the diameter of which (marked d inFIG. 3d) is slightly smaller than that of accepting bore28.

The diameter d of the circle inscribing the body40is for example about 0.1 mm. smaller than the lower tolerance of the diameter of an accepting bore28(seen inFIG. 3b) into which it is inserted.

Optionally, in order to further improve the alignment accuracy, plurality of wedge-shaped nibs42are arranged on at least three of the polygonal body vertexes, forming a snug fit when inserted into the accepting bore28. The inscribing circle of the plurality of wedge-shaped nibs42, has a diameter (marked D inFIG. 3d) slightly bigger than that of accepting bore28so as to provide a snug fit when pressed into place therein. Optionally, nibs42are flexible such that aligners36and36amay be forced into accepting bore28by hand force.

In a specific configuration as shown inFIGS. 2a-fthe body40of aligner36,36aaccepts a circular shape having a diameter (marked d inFIG. 3d), and the wedge-shaped nibs42are formed around the circumference of the face portion40of the circular aligner36so as to provide a snug fit when aligner36,36ais properly inserted into a typical accepting bore28. The outer diameter (marked D inFIG. 3d) of aligner36,36aincluding the plurality of wedge-shaped nibs42is optionally slightly bigger than the maximum acceptable diameter of the accepting bore28. This ensures perfect alignment in all cases, specifically since most field work is accomplished with manually drilling of bore28, and such manual drilling cannot be precise. The present invention advantageously allows for this inaccuracy by providing these wedge-shaped nibs42. It should be noted that the nibs42are not essential to the invention, and an aligner as described above without the nibs42will perform sufficiently well. Nevertheless, the wedge-shaped nibs42makes the aligning more accurate and the alignment process easier to operate on the entire size range of threaded self tapping inserts.

The aligner36,36afurther comprises a recess for attaching the aligner to bolt22(seen inFIG. 3c). The recess or other attachment means, such as collar38(FIG. 3d) formed to snap-fit onto the threaded end portion of a drive bolt22(FIG. 3a). InFIGS. 2dto2f, the collar ring bore is shown open to both directions, however, the bore end facing the workpiece30direction is optionally provided with a circular conical edge43(FIG. 2d) serving as a stopper to prevent further travel of the aligner along drive bolt22. The conical edge43is resting against the chamfered edge normally found on bolts and specifically on drive bolt22, thus further saving space in the accepting bore28as will be hereinafter explained.

The aligner36,36aor54(FIGS. 8a-c) is preferably made of plastic, but any suitable rigid or semi rigid materials may also be used.

FIG. 2bshows the central axis44of aligner36which is automatically centered and self-aligned with its accepting bore central axis34(FIG. 3b). When attached to a drive bolt22(FIGS. 3a,3b), and initially inserted into an accepting bore28(FIG. 3b), the aligner36is constrained to maintain the axial alignment of the drive bolt22with the accepting bore central axis34to prevent the risk of misalignment, as was shown inFIG. 1for the prior art.

FIG. 3ais an exploded view of assembly46(FIGS. 3b,3c) showing the aligner36ofFIGS. 2a-cin relation to the other components needed for a typical self-tapping insert installation configured in accordance with one embodiment of the present invention. A hexagonal-head drive bolt22is inserted into a thread-less hexagonal bush24and threaded into a self-tapping insert26, shown by way of example as having three, tapping apertures27formed equidistantly around the lower portion thereof. However, any type of self-tapping insert can be used.

An aligner36is attached by snap-fitting it to the lower extended portion of the drive bolt22prior to insertion of the above units as an assembly46(FIGS. 3,4,5) into an accepting bore28of a work piece30(FIG. 3b). This helps to maintain axial alignment between the accepting bore central axis34and the drive bolt central axis32.

Hexagonal bush24, has no internal threads, but only serves to enable removing of drive bolt22from the self-tapping insert26without slackening the insert26itself when installation is complete.

The first embodiment of the present invention shown inFIGS. 3a-dis intended for use with all kinds of internal threads, with emphasis on those of small-to-medium size. The drive bolt22can be provided with any type of head, such as a hexagonal-head, a socket hexagonal head or a Torx head as are known to those skilled in the art.

FIG. 3bshows a side view of the insert26and installation components22,24,36fromFIG. 3aready for initial insertion into a pre-drilled accepting bore28of a typical work piece30. Work piece30is shown with an outline view of an accepting bore28as indicated by dashed lines, whose central axis34is coaxial with that of assembly46.

The assembly46includes drive bolt22passed through hexagonal bush24and threaded into a self-tapping insert26all known from the prior art. The collar38of the first embodiment of the present invention is temporarily fitted to the exposed end portion of drive bolt22(FIG. 3b). After first step of installation is complete and the drive bolt22and hexagonal bush24are removed, the collar38will loose by itself from its temporary hold on the drive bolt22, and the disposable aligner36will be left in the accepting bore forever.

FIG. 3cis a cross-sectional view along line P-P ofFIG. 3bshowing details of the assembly46and a clearer view of accepting bore28in work piece30.

FIG. 3dis an enlarged, cross-sectional, view of the circled area marked Q inFIG. 3c. With attention to the aligner36which has been snap-fitted to the exposed portion of drive bolt22which extends beyond self-tapping insert26for a length marked H (FIG. 4c) which is approximately equal to the height marked H′ (FIG. 4c) of the self-tapping insert26in order to assure alignment between the assembly46and the central axis34of accepting bore28.

The diameter d (FIG. 3d) of the face portion40of aligner36is slightly increased by nibs42to a diameter D. Because nibs42are compressible by nature of the semi rigid material, they are forced inwardly to accept and maintain the exact diameter of the accepting bore which may vary between the diameter d and the diameter D of the inscribing circle of the plurality of wedge-shaped nibs42as a result of the non accurate field drilling process described above.

As mentioned above it is one object of the present invention to provide a method of aligning a self tapping threaded insert in its accepting bore.

Accordingly,FIGS. 4a-care views of the assembly46ofFIG. 3showing a first step in the method of aligning a self tapping insert during installation in an accepting bore.

Referring now toFIG. 4athere is shown one embodiment of the method of the present invention for inserting a self tapping insert26into an accepting bore28which was pre-drilled in a work piece30. A typical hand tool, such as an open-end wrench48ais shown by way of example, but other types of suitable tools, optionally including power tool, may be used for this purpose.

The method of the present invention includes a number of steps as will be explained hereinafter with reference toFIGS. 4ato7c. Once the aligner36has been attached to the exposed end of drive bolt22, using the attachment means, such as collar38(FIG. 2), the assembly46is constrained to be coaxial with the central axis34of accepting bore28(seeFIG. 3b) and the self-tapping insert26is therefore also fully aligned.

An upper alignment rest point is formed when the first threads of self-tapping insert26are initially inserted into the opening of accepting bore28in work piece30, and a lower alignment rest point is formed by the aligner36which is snugly fitted into accepting bore28. Since two spaced-apart alignment rest points are established in this way, the entire assembly46including the drive bolt22act as an axial supporting means to align insert26with central axis34(seeFIG. 3b) of accepting bore28, accomplishing the purpose of the use of aligner36as an aligning tool.

FIG. 4bshows a side view of insert assembly46aligned and ready for insertion into work piece30. It should be noted that during this step the three apertures27are substantially above the surface of work piece30(only one is visible). This allows burrs created from the initial tapping and threading action of self-tapping insert26to be released from accepting bore28although their interior side is obstructed by the drive bolt22. The tapping action is performed by rotating assembly46in the direction marked by an arrow by open-end wrench48a(for the case of right hand tapping).

FIG. 4cis a cross-sectional view along line R-R inFIG. 4bindicating the dimension H of the depth from the surface of work piece30to the face of aligner36which is approximately equal to the dimension H′ which is the self-tapping insert26overall height.

FIG. 5is an isometric view of following step of the method of the present invention, after a few turns of installation of the insert by drive bolt22have been obtained; now all 3 apertures27are hidden under the surface of workpiece30. Insert26is now locked into correct position within accepting bore28. A momentary counter torque (symbolized by curved arrows) applied now to a second wrench48bwhile rotating drive bolt22with wrench48ain a counterclockwise loosening movement enables removing drive bolt22and hexagonal bush24while leaving insert26intact. Note that all description herein is for right-hand thread inserts, and reverse directions are used for left-hand inserts.

Aligner36is optionally made of inexpensive material such as plastic and intended for one-time use. Aligner36is stripped off drive bolt22by coming against self-tapping insert26when drive bolt22is loosened and the hexagonal bush24and drive bolt22are removed to prepare for the next step in the method of the invention as will be explained hereinafter.

Although aligner36has accomplished its purpose, it remains inside accepting bore28. Depending on the tightness of fit, aligner36may remain adjacent to self-tapping insert26or may slip further down accepting bore28. In either case, it does not interfere with the practical aim of threading a new machine screw into the inner threads25(FIG. 3a) of self-tapping insert26disposed within work piece30. Aligner36is no longer needed for alignment purposes, and it is unimportant and unnecessary to remove it. The effective height of accepting bore28consumed by the remaining aligner36and specifically the open ended aligner36aas shown inFIGS. 2dto2fis minimal and typically the accepting bore should be deeper than the end face of the drive bolt by only 2 mm to 3 mm depending on the size of the threaded self tapping insert.

FIGS. 6a-care various views of continuing steps in the method of the present invention.

FIG. 6ais an exploded view of the insert26and installation components for the following method step of the present invention. In addition to the above described components of step1, the drive bolt22is now fitted with an extension sleeve50. Accordingly, assembly52(FIG. 6b) comprises a drive bolt22which is inserted through hexagonal bush24and thence through an extension sleeve50to sit over self-tapping insert26provided with three apertures27(only one is visible).

FIG. 6bshows a side view of the assembly52made of the components fromFIG. 6a. The three apertures27of the self-tapping insert26are already hidden under the surface of workpiece30as described above in relation to the previous method step. Adding extension sleeve50ensures that the threaded end of drive bolt22is above the three cutting edges apertures27(FIG. 6c), leaving them open for burrs to be removed. The height of extension sleeve50is designed with this in mind, alternately a shorter drive bolt may be used for this method step without extension sleeve50.

Optionally, extension sleeve50may be provided with a circular protrusion on one face (not shown) smaller in diameter than accepting bore28, intended to locate the upper face of self tapping insert26slightly below the surface of workpiece30.

FIG. 6cis a cross-section view along line S-S inFIG. 6b. Self-tapping insert26is shown already set within a first few threads made in accepting bore28and the drive bolt22, hexagonal bush24, and extension sleeve50are assembled and disposed on top of self-tapping insert26and tightened against it. By further rotating drive bolt22, insert26is further inserted and set flush with or slightly below (as explained above) the upper surface of work piece30. Aligner36has already been stripped from drive bolt22as explained heretofore in relation toFIG. 5and is depicted here as disposed just below self-tapping insert26within accepting bore28.

FIGS. 7a-bare various stages in the method for utilizing an extension sleeve for controlled insertion and seating of a self-tapping insert26within an accepting bore28.

FIG. 7acontinues the method of the present invention depicting the final step in the method of the present invention, the loosening and removal of drive bolt22, hexagonal bush24and extension sleeve50. A second wrench48bapplies counter torque to wrench48aunlocking the components for removal.

FIG. 7bshows a work piece30of the final disposition of self-tapping insert26shown flush with the surface of work piece30.

Self-tapping insert26is selected for use based on the dimensions of its inner threads25(FIG. 3a) which are sized to accommodate a particular size of a machine screw according to the requirements of the fastener needed in a specific application.

FIGS. 8aand8bshow a top isometric and bottom isometric views, respectively of a second embodiment of the present invention for use with sufficiently large self tapping insert thread to allow implementation.

This second embodiment of the present invention provides an aligner54for use with a drilled through drive bolt64(seen inFIG. 9a) whose diameter is large enough so as to conveniently allow forming a central bore66axially therethrough as a practical matter. The large enough diameter of drilled through drive bolt64can accommodate the central bore66in which an extension shaft60can be inserted therethrough and attached to aligner54by an attachment means, such as central aperture56(seeFIG. 8a).

FIG. 8cshows a side view of the aligner54fromFIGS. 8a,8battached to extension shaft60. aligner54is provided with a central bore56, and optionally a plurality of compressible wedge-shaped nibs42, and mounted on an extension shaft60for insertion into an accepting bore28(seeFIGS. 9aand9c).

Aligner54is preferably made of plastic, but any suitable semi rigid materials may also be used.

FIGS. 9a-cshow various views of the second embodiment of the invention as described in relation toFIGS. 8a-c.

FIG. 9ais an exploded view of the embodiment of the present invention fromFIG. 8. Assembly62(FIG. 9b) comprises: a hexagonal-head drive bolt64provided with a central bore66, an extension shaft60, a thru-hole hexagonal bush24, a self-tapping insert26and aligner54. Note that the hexagonal-head drive bolt64is preferably short and when bolted, its threaded end face is above the 3 apertures27leaving them open for burrs to pass through. Accordingly there is no need for the extension sleeve50while employing this second embodiment of the present invention. The method of applying the invention using this second embodiment will not require the step of removing the drive bolt64for placement of the extension sleeve50. The installation requires only one continuous step of insertion of a self tapping insert26until its top face is flat with the workpiece surface level.

FIG. 9bshows a side view of the insert26and installation components forming assembly62aligned and ready for insertion into an accepting bore28(FIG. 9a) of a workpiece30.

FIG. 9cis a cross-sectional view along line T-T inFIG. 9b. Extension shaft60directs aligner54, to which it is removably attached (seeFIG. 8c), to be seated at a low point within accepting bore28. Alternatively, aligner54may be placed there prior to insertion of insert assembly62. Extension shaft60passes through central bore66in drive bolt64to engage with the attachment means, such as central aperture56(seeFIG. 8a-b) of aligner54.

As explained above in relation toFIGS. 4 to 7, an upper alignment rest point is formed when the threads of self-tapping insert26are initially inserted into the opening of accepting bore28in work piece30, and a lower alignment rest point is formed by the aligner54which is snugly fitted into accepting bore28, and fitted to the extension shaft60which is pushed into the central bore56of the aligner54. Since two spaced-apart alignment rest points are established in this way, the entire assembly62including the drive bolt64act as an axial supporting means to align insert26with central axis of accepting bore28, accomplishing the purpose of the use of aligner54as an aligning tool. Since shaft60is free to longitudinally slide in the bore66of drive bolt64the insertion process may be accomplished in one operation.

FIGS. 10ato12bshows different aligners made in accordance with additional embodiments of the present invention.

FIG. 10bdescribes an aligner70made of thin resilient material such as carbon steel, stainless steel or phosphor bronze for instance. The aligner is constructed in the shape of a spring type shaft-retaining-ring of the kind used with ungrooved shafts. The springy fingers72protruding from the inner circumference of ring74towards the center, are configured to match the internal diameter of the drive bolt22thread and serve as attachment means instead of the collar ring38described herein-above with reference toFIGS. 3cand3d. The aligner70may be provided flat and adopt the thread pitch while fitted to the exposed threaded end of drive bolt22(FIG. 10a); or provided with the fingers72already bended to match the drive bolt22pitch. The aligner70may be further provided with external fingers (not shown) protruding on the outer circumference of ring74, sufficiently upwardly bended, to provide same snug fit functionality as the wedge shaped nibs42described herein-above with reference toFIGS. 2ato2f.

Alternately, in another embodiment as shown inFIG. 11b, the aligner is made as an internally threaded plain washer76. The short internal thread78serves as the attachment means instead of the collar ring38described herein-above with reference toFIGS. 3cand3d. The washer is fitted to the drive bolt22as shown inFIG. 11a

In yet another embodiment as shown inFIG. 12b, the aligner is made as a helical spring washer80having approximately the same slope as the drive bolt22pitch. The spring washer80internal circumference82serves as attachment means while being engaged with the drive bolt22thread as shown inFIG. 12a.

The method of operating aligners70,76and80is similar to the method of operating aligner36,36a. When removing drive bolt22(FIG. 5) the aligner disengages from driving bolt22as it rotates counterclockwise. Optionally, aligners70,76and80are made of weak materials, and/or with relatively loose engagement with driving bolt22such that it would not force self-tapping insert26out when bolt22is removed.

FIGS. 13,14and15illustrate usage of the aligners as described above with reference toFIGS. 10,11and12respectively, fitted to an extension shaft60as described above with reference toFIGS. 8cand9a. As shown inFIGS. 14 and 15, the extension shaft60may be provided with a short thread at one end thereof. It will be understood that attachment means suitable to attach the aligner36to drive bolt22as utilized with the first embodiment of the invention may also fit the extension shaft made according to the second embodiment of the present invention.

The method of operating aligners70,76and80with shaft60is similar to the method of operating aligner54. When removing shaft60, the aligner disengages from it by rotating the shaft counterclockwise. Optionally, aligners70,76and80are made of weak materials, and/or with relatively loose engagement with shaft60such that it would not force self-tapping insert26out when the shaft is removed. Optionally, aligners70,76and80disengage from shaft60simply by pulling hard enough on the shaft.

It will therefore be appreciated that the device described herein and illustrated in the accompanying drawings is set forth merely for purposes of example and that many other variations, modifications, and applications of the present invention may be made.

Having described the present invention with regard to certain specific embodiments thereof, it is to be understood that the description is not meant as a limitation, since further modifications may now become apparent to those skilled in the art, and it is intended to cover such modifications as fall within the scope of the description and appended claims.