US3618992A

US3618992A - Expanding dowel construction

Info

Publication number: US3618992A
Application number: US840078*A
Authority: US
Inventors: Lawrence V Whistler Sr; Lawrence V Whistler Jr
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-05-09
Filing date: 1969-05-09
Publication date: 1971-11-09
Anticipated expiration: 1988-11-09

Abstract

A pair of parts to be located and secured to one another are provided with a first hole and a through hole respectively and in alignment with one another. An expandable resilient helical spring dowel is positioned within said holes, and an expanding means cooperates with the dowel to expand it into engagement with the holes to properly align the parts.

Description

States Patent [72] lnventors Lawrence V. Whistler, Sr. [56] References Cited 259 Deneaster Read; UNITED STATES PATENTS Lawrence v-wlisue'ijr-izsl 1,829,657 10/1931 Jones 85/64 Road, both of Kenmore, N.Y. 14217 2,257,538 9/1941 Schlueter. 85/70 21 AppLNo. 840,078

22 d M 9 1969 2,566,573 9/1951 Lyon 85/64 d 2,901,787 9 1959 Whistler, Sr. el al. 85/85 1 meme 3,008,368 11/1961 Hammittetal. 287/189.36F

Continuation-impart of applicahon Ser. No. 755151 A 26 1968 M d ed 3,139,786 7/1964 Ardell 85/7 5' 1,212,298 1 1917 Weston 85/64 2,872,838 2/1959 Vogel 287/189.36F FOREIGN PATENTS 736,625 6/1943 Germany 85/64 Primary Examiner-Edward C Allen AnomeySnyder 8L Butrum [54] SOWFLSONSTRUCTION ABSTRACT: A pair of parts to be located and secured to one anus rawmg another are provided with a first hole and a through hole [52] U.S. C1 ..287/20.92E, respectively n in gnm n with n r. An e p a 85/64,287/189 36F ble resilient helical spring dowel is positioned within said {51] 1111.0 E044: 3/00 holes, and an xp g means cooperates h h dowel to [50] Field of Search 85/64, 63, e pand it into engagement with the holes to properly align the 70; 287/189.36 F 20.92 E,l27, 189.36 F

parts.

PATENTEDuuv 9 I971 3,618,992

SHEET 1 [IF 2 6 52 L i/ {53 [W l "l2 i 3 T Is 40 Q g:

LAWRENCE V. WH/STL SR8 LAWRENCE V. WH/STL JR.

ATTORNEYS EXPANDING DOWEL CONSTRUCTION CROSS REFERENCE TO RELATED APPLICATION The present application is a continuation-in-part of copending United States patent application Ser. No. 755,151, filed Aug. 26, 1968 and now abandoned.

BACKGROUND OF THE INVENTION The present invention relates to metal dowels of the type employed for accurately locating one metal part with respect to another such as machine tool sections, die sections, jig and fixture sections and any type of equipment that requires accurate alignment and doweling where very close tolerances are involved within a range of 0.0005 inch or less.

In the machine and tool industry, it is often necessary to locate one section or part very accurately with respect to another section or part. In some instances, knockout holes are drilled through a machine or tool part to enable the removal of dowel pins. However, in many cases, the design of the product does not allow such knockout holes to be drilled through the machine or tool part since such a hole would interfere with other assemblies and components. Accordingly, in such instances blind holes are formed in the part for receiving a dowel means.

It is also necessary when cleaning, changing or repairing such structures to remove certain machine tools or mechanical sections, whereupon the parts must be relocated in their exact original position. Accordingly, it often becomes necessary to remove dowel means from blind holes, whereupon the dowel means must subsequently again be associated with such blind holes.

In machining various dowel holes for receiving dowel means, the holes may be drilled and reamed, bored, drilled or bored, and ground, and in carrying out such procedures, different dowel holes are often slightly oversized or undersized by approximately one-half a thousandth of an inch or so, whereby standard dowel pins of an exact size cannot be used since they will not expand or contract.

Accordingly, it is desirable to provide dowel means which can be readily inserted and removed from a blind hole, and which at the same time is adapted to be secured in close fitting relationship within dowel holes of slightly different size to thereby provide very accurate alignment of the associated parts.

SUMMARY OF THE INVENTION In the present invention, an expandable resilient hardened and ground spring dowel is provided in association with an expanding means which expands the dowel into engagement with the associated holes. In one form of the invention, the expanding means is adapted to apply pressure to one end of the resilient hardened and ground spring dowel, and this pressure causes the entire spring to expand uniformly throughout its length so that the entire resilient dowel is brought into engagement with the associated dowel holes.

In the first form of the invention, the expanding means is threaded and cooperates with threads formed on one of the parts whereby sufficient pressure may be applied to the expandable dowel so as to ensure tight engagement in the associated dowel holes thereby affording proper alignment of the associated components.

In a further modified form of the invention, the spring dowel is provided with a tapered bore formed longitudinally therethrough. The expanding means is provided with a tapered outer surface which engages the tapered bore fonned within the spring dowel to expand the spring dowel outwardly. This tapered expanding means may also be threaded into one of the parts as aforedescribed.

In still a further modified form of the invention, the spring dowel is provided with a tapered bore formed longitudinally therethrough and an expanding means is provided having a tapered surface formed on the outer surface thereof for engaging the tapered bore to expand the spring dowel. In this latter modification, the expanding means is driven into place rather than being threaded into operative position.

A threaded end portion is provided on the dowel means, and in this case the threaded end portion is exposed at one face of the part having the through hole formed therethrough whereby a pull nut can be applied to this exposed threaded end of the expanding means for removing the expanding means when so desired.

The expandable dowel construction of the present invention ensures proper alignment of dowel holes which may be slightly oversized or undersized. Additionally, the expanding means may be readily inserted or removed from operative position, and the expandable dowel itself can be easily inserted into the alignment holes and subsequently removed with the use of a suitable tool.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a sectional view through an expanding dowel construction according to the present invention,

FIG. 2 is a sectional view taken substantially along line 2-2 of FIG. 1 looking in the direction ofthe arrows,

FIG. 3 is a sectional view illustrating a modified form of the invention,

FIG. 4 is a sectional view of still another form of the invention,

FIG. 5 is a sectional view illustrating a tool used in removing the spring dowel of the present invention,

FIG. 6 is a sectional view illustrating a further modified form of the invention,

FIG. 7 is a sectional view illustrating yet another modified form of the invention,

FIG. 8 is a vertical section through a portion of the structure shown in FIG. 7, illustrating the spring dowel in cross section,

FIG. 9 is a top view of the structure shown in FIG. 8, and

FIG. 10 is a view partly broken away of a pull nut for use with the structure shown in FIGS. 7 through 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings wherein like reference characters designate corresponding parts throughout the several views, a first form of the invention is illustrated in FIGS. 1 and 2. A pair of parts to be located and secured to one another are indicated by reference numerals l0 and 12. In a typical example, member 10 may comprise a die shoe or punch holder, and member 12 may comprise a die block, a punch block of hardened tool steel, machine sections or parts of jigs and fixtures.

Part 10 is provided with a first pair of blind holes 16 which are aligned with through holes 18 formed in part 12, member 12 being counterbored at 20. The retaining clearance holes receive bolting and capscrews 24 for holding

parts

10 and 12 together.

Part number 10 is provided with predrilled and tapped blind holes 30, part 10 being counterbored to provide the substantially cylindrical holes 32 therein which are adapted to be aligned with similar cylindrical through holes 36 formed in part 12. Holes 30 may also be drilled through member 10 in some cases to allow air to escape where a tight fitting capscrew or bolt is employed as illustrated in phantom lines in FIG. 1.

A pair of expandable resilient hardened spring dowels are indicated by reference numeral 40, these spring dowels having a special sharp helical wind. The springs define a central substantially cylindrical bore 42 extending longitudinally therethrough, and it will be seen that the spring dowels are of a relatively thick-walled section and additionally have a wide wall as indicated by the dimension w on FIG. I.

The outside diameter of the spring dowel is ground to approximately 0.001 inch under a standard dowel size. For example where the dowel is to be employed with a 0.500 diameter dowel hole, the dowel spring will be ground to have an outer diameter of 0.499 inch. This enables the spring dowel to be easily assembled within the associated dowel holes in the two

parts

10 and 12. When the spring dowel is compressed, it is capable of expanding and contracting from about 0.002 to about 0.004 inch in diameter, and the expansion of the dowel will cause the two parts 10 and I2 to be aligned in the proper orientation with respect to one another.

It will be noted as seen in FIG. I that the spring dowels 40 extend substantially throughout the hole portions 32 formed in part It) and also extend a substantial distance upwardly within the hole portions 36 formed in part 12 so that when the spring dowels are expanded, it will properly align the two parts.

The expanding means for expanding the dowels 40 comprise a pair of similar bolts or capscrews indicated generally by reference numeral 50. Each of these members includes an enlarged head 52 and a reduced shank portion 54 the lower end 56 of which is threaded and of such a size as to be threaded into the holes 30 formed in member 10. A washer 53 is disposed intermediate the undersurface of each of the enlarged heads 52 and the upper surface of the associated spring dowel 40. The elongated shanks 54 of members 50 extend through the bores 42 formed within the springs 40.

When a close fitting thread is provided on portions 56 and holes 30, it may be necessary to release compressed air, and accordingly relief means is provided for venting air in the form of an elongated longitudinally extending groove 60 formed in the lower threaded end portion 56 of member 50.

As seen in FIG. 1, only a small space indicated by dimension X at the interface of

members

10 and 12 is not engaged by the solid metal of the dowel. When the dowel is compressed, the distance between the coils of the spring dowel is reduced thereby further reducing the dimension of the space X so that the two

members

10 and 12 will be accurately aligned.

Referring now to FIG. 3 of the drawings, a modified form of the invention is illustrated. Parts similar to those described in connection with FIG. 1 have been given the same reference numerals. The only difference in this modification of the invention from that previously described is the form of the expanding means. The capscrew or bolt of the previously described form of the invention has been eliminated.

In the modification shown in FIG. 3, the upper part of the through hole 36 provided through part 12 is provided with a tapered pipe thread 70. A tapered pipe plug 72 is threaded into the thread portion 70 and the undersurface of this pipe plug engages a washer 74 which rests on the upper surface of the spring dowel to transfer pressure to the upper surface of the dowel to expand the spring as hereinbefore described.

The plug 72 is provided with a central recess 76 which is in communication with a hole 78 which is in turn in communication with the hole formed through the washer 74 whereby these holes provide a relief means for venting air from the assembly when the spring dowel is compressed.

Referring now to FIG. 4 of the drawings, here again the structure is similar to that shown in FIG. I and the same parts have been given the same reference characters. In this form of the invention, the upper portion of the through holes 36 formed in part 12 is provided with threads 80 which are adapted to receive a straight threaded plug 82.

The undersurface of plug 82 engages a washer 84 which rests on the upper surface of spring dowel 4 .0 and is adapted to apply pressure thereto for compressing and expanding the spring dowel.

Plug 82 is provided with a central recess 86 which is in communication with a hole 88 formed therethrough. This hole 88 is in turn in communication with a hole formed through the washer 84 so that air may be vented from the interior of the assembly when the spring dowel is compressed and expanded.

Referring now to FIG. of the drawings, the manner in which the spring dowel is removed from the parts and I2 is illustrated. The plug 82 and washer 84 have been removed from the structure as shown in FIG. 4, and a tool indicated generally by reference numeral 90 is then employed for pulling the spring dowel out of the aligned holes formed in

parts

10 and 12.

This tool includes a handle portion 92 and an elongated depending portion 94 having a bowed part 96 formed at a lower part thereof and terminating in a lower offset portion 98.

The tool is adapted to be inserted into the operative position shown in FIG. 5 wherein the offset portion 98 at the lower end thereof is adapted to be positioned within a groove of the helical spring 40. The tool 90 can then be lifted upwardly to pull the spring dowel out of the aligned holes formed in the two

parts

10 and 12.

Referring now to FIG. 6 of the drawings, a further modified form of the invention is illustrated and parts similar to those described in connection with FIG. 1 have been given the same reference numerals.

In this form of the invention, a spring dowel I00 is provided substantially of the same construction as that previously described, the only difference being that rather than having a cylindrical bore formed therethrough which may have a clearance with respect to the associated expanding means, spring dowel 100 has a tapered bore 102 formed therethrough which tapers downwardly to a smaller dimension as seen in FIG. 6. It is, of course, understood that the outside diameter of the spring dowel remains cylindrical.

The expanding means 106 in this form of the invention comprises a pin having a tapered outer surface 108 which is engageable with the tapered bore 102 formed in a spring dowel for expanding the spring dowel outwardly into operative position. The lower reduced end portion I 10 of the pin is threaded and is threaded within the hole 30 provided in part I0. The upper end of pin 106 is provided with a hole or socket 112 of hexagon configuration for receiving a hex wrench and the like whereby the pin may be selectively rotated for moving it into and out of operative expanding position.

Referring now to FIGS. 7-9 inclusive, yet another modification of the present invention is illustrated, and parts similar to those described in connection with the previous figures have been given the same reference numerals primed. In this modification, the spring dowel 100 is of identical construction to that described in connection with FIG. 6.

The expanding means in this form of the invention comprises a pin having a tapered outer surface 122 which is engageable with the tapered bore formed through the spring dowel for expanding the spring dowel upon relative longitu dinal movement of the expanding means with respect to the dowel. In this modification, the expanding means is not urged into expanding relationship by a cooperating threaded connection between the expanding means and one of the parts as in all of the previously described modifications, but the expanding means is driven downwardly as seen in FIG. 7 into its expanding relationship with respect to the spring dowel.

Pin 120 is provided with a substantially cylindrical threaded upper end portion 124 which enables the pin to be withdrawn from the operative position when so desired.

Referring now to FIG. 10, a pull nut indicated generally by reference numeral is illustrated, this pull nut being utilized for removing pin 120 from the operative position shown in FIG. 7. The pull out includes a threaded recess 132 in the bottom end thereof which is adapted to be threaded onto the upper threaded end 124 of pin 120. The pull nut also includes an enlarged head 134 having a hexagonally shaped hole or socket formed therein for receiving a hex wrench or similar tool for operating the pull nut.

As this invention may be embodied in several fonns without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, and since the scope of the invention is defined by the appended claims, all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents are therefore intended to be embraced by those claims.

We claim:

I. An expanding dowel construction including first and second parts to be located and secured to one another, a first one of said parts having a first hole formed in one surface thereof, a second one of said parts having a through hole therein and aligned from said first hole, said first and through holes being concentric relative to each other and at least in part of the same diameter, said second part abutting said one surface to the first part, an expandable resilient coil spring dowel positioned at least partly in said first hole and partly in said through hole, expanding means associated with said dowel for expanding the dowel within said hole to properly align said first and second parts with respect to one another, said first part having a third hole formed in said one surface thereof, said second part having another through hole therein aligned with said third hole, fastening means securing said first and second parts to each other through said third hole and another through hole, and a clearance between said another through hole and said fastening means whereby said first and second parts may shift relative to each other upon the expansion of said expandable spring dowel incident to the securement of said first and second parts to each other by said fastening means.

2. Apparatus as defined in claim 1 wherein said expanding means includes a threaded portion, one of said parts having a cooperating threaded portion for receiving the threaded portion of said expanding means.

3. Apparatus as defined in claim 2 wherein said spring dowel is hardened and ground and has a sharp helical wind.

4. Apparatus as defined in claim 3 wherein said spring is of relatively thick-walled construction.

5. Apparatus as defined in claim 4 wherein said spring also has a relatively wide wall.

6. Apparatus as defined in claim 2 including relief means to vent air which may be compressed upon operation of said expanding means to expand the associated dowel.

7. Apparatus as defined in claim 6 wherein said relief means includes a relief portion formed in said expanding means.

8. Apparatus as defined in claim 2 wherein said expanding means comprises an elongated screw having a threaded end portion, said threaded end portion being threaded into said first part.

9. Apparatus as defined in claim 8 wherein said screw has a longitudinally extending relief groove formed at the threaded end thereof.

10. Apparatus as defined in claim 2 wherein said expanding means comprises a threaded plug, said plug being threaded into said second part.

11. Apparatus as defined in claim 10 wherein said plug has a relief hole formed therethrough.

12. Apparatus as defined in claim 2 wherein said spring dowel has a sharp helical wind and is made of comparatively wide and heavy steel ribbon with a very small space between coils.

13. Apparatus as defined in claim 2 wherein said dowel has an expanding and contracting action of about 0.004 inch.

14. Apparatus as defined in claim 2 wherein said spring dowel has a tapered bore extending longitudinally therethrough.

15. Apparatus as defined in claim 14 wherein said expanding means has a tapered outer surface for engaging the tapered bore in said spring dowel to expand the spring dowel upon relative axial movement of the expanding means with respect to the spring dowel.

16. Apparatus as defined in claim 15 wherein said expanding means includes a threaded end portion, said threaded end portion being threaded into said first part.

17. Apparatus as defined in claim 1 wherein said spring dowel has a tapered bore formed longitudinally therethrough.

18. Apparatus as defined in claim 17 wherein said expanding means has a tapered outer surface thereon for engaging the tapered bore of said spring dowel to expand said spring dowel.

19. Apparatus as defined in claim 18 wherein said expanding means includes a threaded end portion, said threaded end portion being accessible from the opposite side of said second part so that a pull nut is engageable with said tapered end portion for removingsaid ex andingmeanswhen desired,

20. Apparatus as de med in claim 1 wherein said spring

Claims

1. An expanding dowel construction including first and second parts to be located and secured to one another, a first one of said parts having a first hole formed in one surface thereof, a second one of said parts having a through hole therein and aligned from said first hole, said first and through holes being concentric relative to each other and at least in part of the same diameter, said second part abutting said one surface to the first part, an expandable resilient coil spring dowel positioned at least partly in said first hole and partly in said through hole, expanding means associated with said dowel for expanding the dowel within said hole to properly align said first and second parts with respect to one another, said first part having a third hole formed in said one surface thereof, said second part having another through hole therein aligned with said third hole, fastening means securing said first and second parts to each other through said third hole and another through hole, and a clearance between said another through hole and said fastening means whereby said first and second parts may shift relative to each other upon the expansion of said expandable spring dowel incident to the securement of said first and second parts to each other by said fastening means.

19. Apparatus as defined in claim 18 wherein said expanding means includes a threaded end portion, said threaded end portion being accessible from the opposite side of said second part so that a pull nut is engageable with said tapered end portion for removing said expanding means when desired.

20. Apparatus as defined in claim 1 wherein said spring dowel has an outer diameter slightly less than the diameter of said holes thereby enabling the spring dowel to be easily inserted and removed with respect to said holes.