US3248747A - Fluteless taps - Google Patents
Fluteless taps Download PDFInfo
- Publication number
- US3248747A US3248747A US317192A US31719263A US3248747A US 3248747 A US3248747 A US 3248747A US 317192 A US317192 A US 317192A US 31719263 A US31719263 A US 31719263A US 3248747 A US3248747 A US 3248747A
- Authority
- US
- United States
- Prior art keywords
- thread
- zone
- primary
- tap
- crests
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21H—MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS
- B21H3/00—Making helical bodies or bodies having parts of helical shape
- B21H3/10—Making helical bodies or bodies having parts of helical shape twist-drills; screw-taps
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23G—THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
- B23G7/00—Forming thread by means of tools similar both in form and in manner of use to thread-cutting tools, but without removing any material
- B23G7/02—Tools for this purpose
Definitions
- Fluteless 4taps are taps which do not cut threads but act by deforming the wall of a cylindrical bore without deliberately removing any material.
- a fluteless tap has a thread with a number of circumferentially spaced radially relieved parts between which there are accordingly circumferentially spaced crests. At their maximum radial distance from the axis of the tap these crests have profiles, as seen in section planes lying along the axis of the tap, corresponding to t-he shape of the thread which is to be formed by the tap.
- the diameter of the tap meaning the diameter of the thread which will be formed by the tap, that is to say -twice the maximum radius of the crests from the axis of the tap.
- a tap has at the leading end a primary thread Zone which has circumferentially spaced crests at a constant radial distance which is less than the radial distance of the crests on the remainder of the tap but is greater than half of lthe crests on the remainder of the tap; that is -to say, the radius of the primary thread Zone is smaller than the radiusA of the remainder by an amount less than half the radial depth of the crests on the remainder.
- the thread on the tap has a smooth transition from the primary thread Zone to the remainder of the thread, which remainder may be termed the secondary thread Zone.
- the primary thread zone on the tap In use when the tap is screwed into a bore of the appropriate diameter, the primary thread zone on the tap partially forms the required thread in the bore, and the thread in the bore is completed by the secondary thread Zone.
- the primary thread zone can enter relatively easily int-o the bore (as compared with a tap with a thread of constant radius all the Way to the end) and is of a constant radius, it ensures that the axis of the tap is accurately aligned with the axis of the bore.
- the primary thread Zone preferably has at least three turns of thread.
- FIGURE l is a fragmentary side view showing the threaded part of the tap.
- FIGURE 2 is a cross section, which for convenience is taken in a helix through 'thencentre of the helical valley between two adjacent turns of the thread.
- the tap has a primary thread zone 2 at its leading end, and a secondary thread zone 4. There are about three turns of the primary thread Zone, and the transition from the primary zone to secondary zone takes place through one turn of the thread.
- the secondary thread zone has an addendum A, that is to say, half the radial depth ⁇ of the final thread which is formed by the secondary zone thread.
- the diameter of the crests of the primary thread zone is equal to the diameter of the secondary thread zone minusthe addendum of the secondary thread zone.
- the secondary thread zone has a pitch diameter P2. It will be seen that this is smaller than the crest diameter of the primary thread zone.
- the primary thread zone has a pitch diameter P1.
- the tap has four circumferentially spaced crests 8. Each crest is at the junction of a steeply relieved leading part 10 and a progressively relieved trailing part 12.
- the tap diameter is the dimension D
- the outer edge of the lead-ing part 10 is substantially a straight line passing through the crest tangentially to a circle M which has the minimum diameter of the tap.
- the outer edge of the progressively relieved trailing part 12 extends from the crest to a point at about the junction of the circle M with the outer edge of the leading part of the adjacent crest.
- the relief of diameter that is to say the difference between the dimension D yand the diameter of the circle M, is shown slightly exaggerated in FIGURE 2 for the sake of clarity.
- FIGURE 2 The thread form shown in FIGURE 2 is the subject of patent application No. 30,995/ 60.
- a lluteless tap having, in axial sequence, a leading end, a primary thread zone, a Itransition thread Zone, and a secondary thread zone; each of the primary and secondary thread zones consisting of a plurality of helical turns, each turn, viewed axially, having a plurality of circumferential-lyvspaced crests, all the crests of the primary thread Zone lying a-t a uniform rst radius from the axis of the tap, and all the crests of the secondary thread Zone lying at a uniform second radius from the axis of the tap; all the thread zones having turns which, considered in planes containing the axis, are of the same profile; Ithe first radius being less than the second radius by an amount not eX- ceeding half the radial depth of the crests on second thread zone; the transition thread zone consisting of about one spiral turn which links the adjacent turns of the primary and secondary thread zones; and the profile of the turns having an apex at its radially outermost extremity
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Forging (AREA)
Description
United States Patent Otitiee 3,248,747 Patented May 3, 1966 Claims priority, application Great Britain, Nov. 1, 1962,
37,134/ 62 2 Claims. (Cl. 10-152) Fluteless 4taps are taps which do not cut threads but act by deforming the wall of a cylindrical bore without deliberately removing any material. For this purpose a fluteless tap has a thread with a number of circumferentially spaced radially relieved parts between which there are accordingly circumferentially spaced crests. At their maximum radial distance from the axis of the tap these crests have profiles, as seen in section planes lying along the axis of the tap, corresponding to t-he shape of the thread which is to be formed by the tap. For convenience we refer to the diameter of the tap, meaning the diameter of the thread which will be formed by the tap, that is to say -twice the maximum radius of the crests from the axis of the tap.
According to the present invention a tap has at the leading end a primary thread Zone which has circumferentially spaced crests at a constant radial distance which is less than the radial distance of the crests on the remainder of the tap but is greater than half of lthe crests on the remainder of the tap; that is -to say, the radius of the primary thread Zone is smaller than the radiusA of the remainder by an amount less than half the radial depth of the crests on the remainder. The thread on the tap has a smooth transition from the primary thread Zone to the remainder of the thread, which remainder may be termed the secondary thread Zone.
In use when the tap is screwed into a bore of the appropriate diameter, the primary thread zone on the tap partially forms the required thread in the bore, and the thread in the bore is completed by the secondary thread Zone. As the primary thread zone can enter relatively easily int-o the bore (as compared with a tap with a thread of constant radius all the Way to the end) and is of a constant radius, it ensures that the axis of the tap is accurately aligned with the axis of the bore. To ensure accurate alignment the primary thread Zone preferably has at least three turns of thread.
An example of a tap according to the present invention is shown in the accompanying drawings. In the drawings:
FIGURE l is a fragmentary side view showing the threaded part of the tap; and
FIGURE 2 is a cross section, which for convenience is taken in a helix through 'thencentre of the helical valley between two adjacent turns of the thread.
The tap has a primary thread zone 2 at its leading end, and a secondary thread zone 4. There are about three turns of the primary thread Zone, and the transition from the primary zone to secondary zone takes place through one turn of the thread.
The secondary thread zone has an addendum A, that is to say, half the radial depth `of the final thread which is formed by the secondary zone thread. The diameter of the crests of the primary thread zone is equal to the diameter of the secondary thread zone minusthe addendum of the secondary thread zone.
The secondary thread zone has a pitch diameter P2. It will be seen that this is smaller than the crest diameter of the primary thread zone. The primary thread zone has a pitch diameter P1.
As shown in FIGURE 2, the tap has four circumferentially spaced crests 8. Each crest is at the junction of a steeply relieved leading part 10 and a progressively relieved trailing part 12. The tap diameter is the dimension D, It will be seen that the outer edge of the lead-ing part 10 is substantially a straight line passing through the crest tangentially to a circle M which has the minimum diameter of the tap. The outer edge of the progressively relieved trailing part 12 extends from the crest to a point at about the junction of the circle M with the outer edge of the leading part of the adjacent crest. The relief of diameter, that is to say the difference between the dimension D yand the diameter of the circle M, is shown slightly exaggerated in FIGURE 2 for the sake of clarity.
The thread form shown in FIGURE 2 is the subject of patent application No. 30,995/ 60.
I claim:
1. A lluteless tap having, in axial sequence, a leading end, a primary thread zone, a Itransition thread Zone, and a secondary thread zone; each of the primary and secondary thread zones consisting of a plurality of helical turns, each turn, viewed axially, having a plurality of circumferential-lyvspaced crests, all the crests of the primary thread Zone lying a-t a uniform rst radius from the axis of the tap, and all the crests of the secondary thread Zone lying at a uniform second radius from the axis of the tap; all the thread zones having turns which, considered in planes containing the axis, are of the same profile; Ithe first radius being less than the second radius by an amount not eX- ceeding half the radial depth of the crests on second thread zone; the transition thread zone consisting of about one spiral turn which links the adjacent turns of the primary and secondary thread zones; and the profile of the turns having an apex at its radially outermost extremity, whereby the part of the primary thread zone adjacent t-o the leading end will exert -a rst thread forging action upon insertion into a bore and thereby form a primary thread, the remainder of the primary thread Zone will maintain the tap in axial alignment in the bore, and the transition thread zone will exert a second thread forging action upon the primary thread and thereby enlarge the primary thread into secondary thread, and the remainder of the secondarythread Zone will smooth the secondary thread.
2. A iiuteless tap according to claim 1, in which the rst radius is substantially equal to the second radius minus one quarter of the radial height of Ithe prole.
References Cited by the Examiner UNITED STATES PATENTS 84,411 ll/l868 Clark et al. 10-141 2,325,627 8/1943 Neilson 10-l4l 2,807,813 10/1957 Welles 10-152 2,991,491 7/1961 Welles 10-15?- ANDREW R. JUHASZ, Primary Examiner.
Claims (1)
1. A FLUTELESS TAP HAVING, IN AXIAL SEQUENCE, A LEADING END, A PRIMARY THREAD ZONE, A TRANSITION THREAD ZONE, AND A SECONDARY THREAD ZONE; EACH OF THE PRIMARY AND SECONDARY THREAD ZONES CONSISTING OF A PLURALITY OF HELICAL TURNS, EACH TURN, VIEWED AXIALLY, HAVING A PLURALITY OF CIRCUMFERENTIALLY SPACED CRESTS, ALL THE CRESTS OF THE PRIMARY THREAD ZONE LYING AT A UNIFORM FIRST RADIUS FROM THE AXIS OF THE TAP, AND ALL THE CRESTS OF THE SECONDARY THREAD ZONE LYING AT A UNIFORM SECOND RADIUS FROM THE AXIS OF THE TAP; ALL THE THREAD ZONES HAVING TURNS WHICH, CONSIDERED IN PLANES CONTAINING THE AXIS, ARE OF THE SAME PROFILE; THE FIRST RADIUS BEING LESS THAN THE SECOND RADIUS BY AN AMOUNT NOT EXCEEDING HALF THE RADIAL DEPTH OF THE CRESTS ON SECOND THREAD ZONE; THE TRANSITION THREAD ZONE CONSISTING OF ABOUT ONE SPIRAL TURN WHICH LINKS THE ADJACENT TURNS OF THE PRIMARY AND SECONDARY THREAD ZONES; AND THE PROFILE OF THE TURNS HAVING AN APEX AT ITS RADIALLY OUTERMOST EXTREMITY, WHEREBY THE PART OF THE PRIMARY THREAD ZONE ADJACENT TO THE LEADING END WILL EXERT A FIRST THREAD FORGING ACTION UPON INSERTION INTO A BORE AND THEREBY FORM A PRIMARY THREAD, THE REMAINDER OF THE PRIMARY THREAD ZONE WILL MAINTAIN THE TAP IN AXIAL ALIGNMENT IN THE BORE, AND THE TRANSITION THREAD ZONE WILL EXERT A SECOND THREAD FORGING ACTION UPON THE PRIMARY THREAD AND THEREBY ENLARGE THE PRIMARY THREAD INTO SECONDARY THREAD, AND THE REMAINDER OF THE SECONDARY THREAD ZONE WILL SMOOTH THE SECONDARY THREAD.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB3713462 | 1962-11-01 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3248747A true US3248747A (en) | 1966-05-03 |
Family
ID=10394011
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US317192A Expired - Lifetime US3248747A (en) | 1962-11-01 | 1963-10-18 | Fluteless taps |
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US (1) | US3248747A (en) |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3656197A (en) * | 1971-04-12 | 1972-04-18 | Balax Inc | Reusable swaging tap |
US3850074A (en) * | 1970-01-30 | 1974-11-26 | Nl Industries Inc | Vibration-resistant thread-forming screw |
US3907017A (en) * | 1974-09-30 | 1975-09-23 | Glenn W Stanwick | Interfering thread form |
JPS60180717A (en) * | 1984-02-27 | 1985-09-14 | O S G Kk | Rolling tap for shrinking female screw effective diameter |
US4845818A (en) * | 1986-07-16 | 1989-07-11 | Perry Oliver L | Device for changing fuel pump on internal combustion engine |
US20060039775A1 (en) * | 2002-10-02 | 2006-02-23 | Hiromichi Mizuno | Tapping screw |
US20060199654A1 (en) * | 2003-08-04 | 2006-09-07 | Lindh Adcock Neil W | Tap and a method of tapping |
DE102005010543A1 (en) * | 2005-03-04 | 2006-09-07 | EMUGE-Werk Richard Glimpel GmbH & Co. KG Fabrik für Präzisionswerkzeuge | Tool for producing an internal thread has thread forming regions protruding radially out from tool axis ed side regions either side of central region to produce differently shaped thread paths in rotational directions |
US20070172333A1 (en) * | 2006-01-09 | 2007-07-26 | Tian-Fu Tsau | Screw member having two different thread angles formed on a sharp-edged thread |
US8011866B2 (en) | 2001-08-20 | 2011-09-06 | Maclean-Fogg Company | Locking fastener assembly |
US20170175796A1 (en) * | 2015-12-18 | 2017-06-22 | General Electric Company | Thread for improved fastener reliability |
EP3199824A1 (en) | 2016-01-28 | 2017-08-02 | SFS Intec Holding AG | Fastening arrangement and use of a fastening arrangement |
US20200324893A1 (en) * | 2019-04-11 | 2020-10-15 | Bell Helicopter Textron Inc. | Aircraft coupling mechanism |
US20210033136A1 (en) * | 2019-08-01 | 2021-02-04 | Eaton Intelligent Power Limited | Hybrid thread geometry for threaded fitting |
US20230122014A1 (en) * | 2020-01-21 | 2023-04-20 | Osg Corporation | Thread forming tap for ballscrew |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US84411A (en) * | 1868-11-24 | Improved screw-tap | ||
US2325627A (en) * | 1941-10-02 | 1943-08-03 | John E Castle | Thread cutting tool |
US2807813A (en) * | 1956-04-03 | 1957-10-01 | Besley Welles Corp | Fluteless swaging taps |
US2991491A (en) * | 1958-11-21 | 1961-07-11 | Besly Welles Corp | Fluteless swaging tap with sizing area increasing at a constant rate |
-
1963
- 1963-10-18 US US317192A patent/US3248747A/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US84411A (en) * | 1868-11-24 | Improved screw-tap | ||
US2325627A (en) * | 1941-10-02 | 1943-08-03 | John E Castle | Thread cutting tool |
US2807813A (en) * | 1956-04-03 | 1957-10-01 | Besley Welles Corp | Fluteless swaging taps |
US2991491A (en) * | 1958-11-21 | 1961-07-11 | Besly Welles Corp | Fluteless swaging tap with sizing area increasing at a constant rate |
Cited By (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3850074A (en) * | 1970-01-30 | 1974-11-26 | Nl Industries Inc | Vibration-resistant thread-forming screw |
US3656197A (en) * | 1971-04-12 | 1972-04-18 | Balax Inc | Reusable swaging tap |
US3907017A (en) * | 1974-09-30 | 1975-09-23 | Glenn W Stanwick | Interfering thread form |
JPS60180717A (en) * | 1984-02-27 | 1985-09-14 | O S G Kk | Rolling tap for shrinking female screw effective diameter |
US4845818A (en) * | 1986-07-16 | 1989-07-11 | Perry Oliver L | Device for changing fuel pump on internal combustion engine |
US8011866B2 (en) | 2001-08-20 | 2011-09-06 | Maclean-Fogg Company | Locking fastener assembly |
US20060039775A1 (en) * | 2002-10-02 | 2006-02-23 | Hiromichi Mizuno | Tapping screw |
US7575520B2 (en) * | 2003-08-04 | 2009-08-18 | Adcock Technology Limited | Tap and a method of tapping |
US20060199654A1 (en) * | 2003-08-04 | 2006-09-07 | Lindh Adcock Neil W | Tap and a method of tapping |
DE102005010543B4 (en) * | 2005-03-04 | 2009-04-09 | EMUGE-Werk Richard Glimpel GmbH & Co. KG Fabrik für Präzisionswerkzeuge | Tool and method for creating or finishing a thread |
DE102005010543A1 (en) * | 2005-03-04 | 2006-09-07 | EMUGE-Werk Richard Glimpel GmbH & Co. KG Fabrik für Präzisionswerkzeuge | Tool for producing an internal thread has thread forming regions protruding radially out from tool axis ed side regions either side of central region to produce differently shaped thread paths in rotational directions |
US20070172333A1 (en) * | 2006-01-09 | 2007-07-26 | Tian-Fu Tsau | Screw member having two different thread angles formed on a sharp-edged thread |
US20170175796A1 (en) * | 2015-12-18 | 2017-06-22 | General Electric Company | Thread for improved fastener reliability |
DE102016101519A1 (en) * | 2016-01-28 | 2017-08-03 | Sfs Intec Holding Ag | Screw, fastening arrangement, use of a fastening arrangement and method for producing a screw |
EP3199824A1 (en) | 2016-01-28 | 2017-08-02 | SFS Intec Holding AG | Fastening arrangement and use of a fastening arrangement |
US10619662B2 (en) | 2016-01-28 | 2020-04-14 | Sfs Intec Holding Ag | Screw, fastening arrangement, use of a fastening arrangement, and method for producing a screw |
US20200324893A1 (en) * | 2019-04-11 | 2020-10-15 | Bell Helicopter Textron Inc. | Aircraft coupling mechanism |
US11724804B2 (en) * | 2019-04-11 | 2023-08-15 | Textron Innovations Inc. | Aircraft coupling mechanism |
US20210033136A1 (en) * | 2019-08-01 | 2021-02-04 | Eaton Intelligent Power Limited | Hybrid thread geometry for threaded fitting |
US11661966B2 (en) * | 2019-08-01 | 2023-05-30 | Eaton Intelligent Power Limited | Hybrid thread geometry for threaded fitting |
US20230122014A1 (en) * | 2020-01-21 | 2023-04-20 | Osg Corporation | Thread forming tap for ballscrew |
US11826844B2 (en) * | 2020-01-21 | 2023-11-28 | Osg Corporation | Thread forming tap for ballscrew |
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