Stud Extractor

Abstract

A hand-operated device for extracting studs from engine blocks or the like embodies an internally screw-threaded body portion having a turning handle means. An intermediate adapter has external and internal threads which enable the adapter to be screwed into the body portion and over the screw threads of an anchored stud. An abutment collar or spacer is interposed between the face of the member in which the stud is anchored and the opposing end of the rotatable body portion. The device has the additional capability of extracting studs which have been broken off above or below the face of the member which holds the studs.

Parent Case Text

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of prior copending application Ser. No. 6522, filed Jan. 28, 1970, now abandoned, for STUD EXTRACTOR.

Description

The prior art contains teachings of devices to extract threaded studs from bodies in which the studs are anchored, such as engine blocks and similar machine components. Such prior art devices generally embody cooperating right and left hand screw-threaded parts which, upon turning in relation to a stud which is anchored to the work by screw-threads, will result in the removal of the stud. These prior art extractors are not suitable for extracting smooth cylindrical studs from bodies or blocks into which they have been tightly press fitted. In order to successfully remove a press fitted stud, it is necessary to engage the stud in such a manner that an even and steady pulling force can be exerted on the stud in a true axial direction. There is a need for a simplified hand-operated extractor or puller for press fitted studs and this need has not been satisfied by the prior art, and therefore the principal objective of the invention is to satisfy this need through the provision of a very simplified, economical and reliable hand-operated device which is easy to operate and involves the smallest possible number of simple components. The stud extractor embodying the invention possesses all of these desirable features and additionally is extremely rugged and durable in construction, compact and includes means for extracting studs which are broken off above or below the face of the body in which they are anchored.

Other features and advantages of the device will become apparent during the course of the following description.

BRIEF DESCRIPTION OF DRAWING FIGURES

FIG. 1 is an exploded perspective view of a stud extractor embodying the invention.

FIG. 2 is a central vertical longitudinal section through the extractor illustrating the normal use thereof for pulling a press fitted stud from a body containing the same.

FIG. 3 is a similar cross sectional view of the device showing the use thereof for extracting a stud which is broken off above the face of the body in which it is anchored and rethreaded.

FIG. 4 is a similar sectional view of the device showing its use for extracting a stud which has been broken off below the face of the body in which it is anchored.

DETAILED DESCRIPTION

Referring to the drawings in detail wherein like numerals designate like parts throughout, the numeral 10 designates an elongated body portion which may have a cylindrical exterior or other convenient shape. The body portion 10 has an internal axial bore 11 which terminates considerably below the top of the body portion as indicated by the end wall 12. The lower portion of the bore 11 is screw-threaded as shown at 13, and near the lower end 14 of the body portion 10 the threaded bore 13 leads into an enlarged diameter recess 15 which opens through the adjacent end of the body portion. The recess 15 is unthreaded and cylindrical.

Near its opposite end and remote from its open end, the body portion 10 has a cross bore 16 which receives removably a handle forming rod 17, releasably secured in place in the normal use position by a spring detent means 18, as indicated. The handle normally projects equidistantly beyond opposite sides of the body portion 10 to facilitate grasping by both hands.

The stud extractor further comprises an intermediate adapter 19 which is generally cylindrical and which has a central internally screw-threaded bore 20 opening through its lower end and extending to a point near the other end of the adapter. The adapter 19 is also externally threaded as indicated at 21 from its lower end upwardly to a point approximatey at its longitudinal center and in any event sufficient to give firm screw-threaded engagement with the internal threads of the body portion 10 when the parts are assembled in their normal use positions. Above the external screw-threads 21, the adapter 19 has a somewhat reduced diameter extension 22 which is unthreaded and which projects with clearance into the cylindrical bore 11 of the body portion 10. The adjacent end of the adapter 19 preferably has an integral hexagonal wrench lug 23, or head, formed thereon. A similar wrench-engageable head 24 is formed on the extreme upper end of the body portion 10 so that it may be engaged at certain times with a wrench if additional turning force is required to extract a stud.

The extractor additionally comprises a stepped collar or spacer 25 having a central bore 26 of sufficient diameter to engage over the largest size stud which the tool must accommodate as well as any smaller sizes. The collar 25 which may be externally cylindrical has an annular shoulder 27 adapted to abut the opposed end 14 of body portion 10. The leading flat end face 28 of the collar 25 abuts the face of an engine block 29 or the like into which a smooth unthreaded cylindrical stud 30 is tightly pressed and anchored. As shown in FIG. 2, a portion of the smooth stud 30 projects above the block 29 and has a screw-threaded terminal portion 31 spaced from the block. The collar 25 has a reduced diameter end portion 32 above the shoulder 27 which is cylindrical and engages slidably within the cylindrical recess 15 of the body portion 10. The lower end of the adapter 19 may abut the top end of the extension 32, as shown in FIG. 2.

Referring to FIG. 1, the element 33 is a conventional cylindrical threading die which is insertable at required times into the recess 15 of body portion 10 for use in rethreading studs which are broken off above the top face 34 of the engine block 29 or the like. This operation will be further described. The threading die 33 is temporarily locked within the recess 15 during use by a set screw 35.

The customary use of the extractor for pulling a normal stud 30 out of an opening in the block 29 in which it is press fitted is as follows. The abutment collar 25 is placed over the top of the stud, FIG. 2, with clearance. The intermediate adapter 19 is threaded onto the screw-threaded end portion 31 of the stud, the latter being received by the threaded bore 20. The lower end of the adapter 19 may or may not contact the top of the collar 25 depending upon the distance between the threaded portion 31 and the surface 34. The internally threaded body portion 10 is now screwed onto the external threads of the adapter 19 and turned downwardly until its lower end 14 engages the annular shoulder 27 of the collar. The body portion 10 is now further tightened downwardly by the use of the handle 17 or with the additional assistance of a wrench, if required, utilizing the head 24. This action will be resisted by the rigid collar 25 and through the intermediate adapter 19 an upward axial pulling force will be exerted on the stud 30 to extract the same cleanly from the body 29. The concentric and coaxial arrangement of the elements 10, 19 and 25 with respect to the stud 30 assures an even and truly axial pull on the stud which is essential to proper extraction without breaking the stud.

FIG. 3 illustrates a modified use of the extractor for removing a stud 30 which has been broken off above the face 34 of block 29. When this occurs, the threading die 33 is mounted in the recess 15 of body portion 10 and this assembly is then used to produce screw-threads 36, FIG. 3, on the top of the broken stud. The adapter 19 is now placed over the threads 36 and after removal of the die 33 from the recess 15, the body portion 10 is applied over the adapter 19 and turned into abutting contact with the solid surface 34. Further rotational tightening of the body portion 10 will produce extraction of the stud in the manner previously described. In the FIG. 3 arrangement, the collar 25 or spacer is not employed due to the shortness of the threaded extension 36. While the use of the collar is preferable for stability and for minimizing wear on the lower end of the body portion 10 nevertheless the extraction of the stud can be successfully achieved with the use of the two components 10 and 19, as shown in FIG. 3.

FIG. 4 shows another manner of using the extractor for pulling a stud 30 which has been broken off below the surface 34 of the block 29. In such a case, the broken stud 30 is drilled and tapped by conventional means to produce a threaded opening 37 in the top of the stud. A connector extension 38 for the broken and threaded stud 30 is inserted into the opening which contains the stud and a reduced diameter threaded portion 39 on the bottom of the connector is received in the threaded opening 37 and is tightened therein. The upper end of the connector extension 38 has a larger threaded portion 40 thereon which engages in the threaded bore 20 of adapter 19 as shown in FIG. 4. Thus, the repaired stud 30 with the connector extension 38 thereon is made structurally the same prior to extraction as the normal unbroken stud 30 in FIG. 2. The extractor including elements 10, 19 and 25 is then employed in FIG. 4 with the extension 38 to extract the broken stud 30 in the same manner described in connection with the normal embodiment of FIG. 2.

It may be seen that the simple tool is quite versatile in its usage in that it can extract normal studs and those that are broken off above or below the workpiece in which they are anchored. The tool is characterized by simplicity and compactness, economy of manufacturing, minimum number of parts, and ease of use.

While the parts of the invention have been described as being used in a vertical position with reference to top and bottom ends of elements, it should be clearly understood that the extractor may be utilized horizontally or in any working position dictated by the mounting of a particular stud.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention or scope of the subjoined claims.

Claims

I claim:

1. A device for extracting a press fitted stud from a member, said stud having a threaded portion projecting beyond the member within which it is anchored, said device comprising an adapter having external screw threads and an internally threaded opening, said internally threaded opening of the adapter receiving the threaded portion of the stud therein, a body portion substantially longer than the adapter and having an internally screw threaded bore receiving the external screw-threads of the adapter, said body portion being telescopically engaged over the adapter and extending above the adapter and having a leading abutment end projecting somewhat below the bottom of the adapter for contact with a stationary reaction face on said member, and turning means located on the body portion on the end opposite said abutment end to facilitate turning it on the axis of the stud to be extracted.

2. The structure of claim 1, and an abutment collar interposed between the leading end of said body portion and a face of said member in which said stud is anchored, said abutment collar having a through body enabling the collar to be placed removably over said stud.

3. The structure of claim 2, and said abutment collar having an annular shoulder directly engageable with the leading end of said body portion and a reduced cylindrical extension projecting axially beyond said shoulder, the body portion having a cylindrical recess in its leading end receiving said cylindrical extension.

4. The structure of claim 3, and a threading die element removably mountable within said recess of the body portion so that the body portion and die may be manipulated separately from the adapter to produce screw-threads on a stud broken off above the member in which it is anchored, the body portion subsequently used with said adapter while threadedly engaged therewith and while the adapter bore is threadedly engaged with the broken stud to extract the stud.

5. The structure of claim 2, and a connector element having a first screw-threaded end portion engageable in the threaded bore of the adapter and a second screw-threaded end portion engageable in a tapped opening in a stud which is broken off below a surface of a member in which it is anchored, the bore of said collar receiving said connector element therethrough.

6. The structure of claim 1, and the threaded portion of said stud and all of the screw-threads of said adapter and body portion being of the same hand.

7. The structure of claim 6, and all of said screw-threads being right hand threads.

8. The structure of claim 1, and said turning means comprising a rod extending transversely of the body portion near its end remote from the stud, the body portion having a transverse through bore receiving the rod so that the latter may extend beyond opposite sides of the body portion, and yielding detent means removably securing said rod within said transverse through bore.

9. The structure of claim 3, and said internally screw-threaded bore of the body portion being coaxial with the through bore of the collar and with said cylindrical recess of the body portion and being of reduced diameter relative to the diameter of the cylindrical recess, the bore of the body portion being of sufficient length to contain bodily the adapter and enabling the adapter to be screwed into the body portion completely with the leading end of the adapter disposed inwardly of the leading end of the body portion.

10. The structure of claim 9, and a wrench-engageable lug formed on one end of the body portion and said adapter to facilitate turning the same, said body portion, adapter, collar and said stud being coaxially arranged and concentric when the device is in a use position with respect to the stud.