US3775792A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thread forming tap
Assignee: Robert Bosch Tool Corp
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Filing: 1972-03-01
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Granted: 1973-12-04
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Expires: 1992-03-01
Abstract
Abstract A tap having a threaded body of polygonal cross-sectional shape in which the thread comprises arcuate portions with V-crests separated by intervening chordal portions having truncated crests, the initial thread turns on the entrant end of the tap having a continuous sharp V-shaped crest.
Inventors
- 👤 D Leonard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:03
CPC Classifications
B; B23; B23G; B23G7/00; B23G7/02
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
155 words
A tap comprising a longitudinal body of generally polygonal shape in cross section having a tapered end and a thread helically arranged about said body and tapered end, the turns of the thread on said longitudinal body being of constant size and shape and consisting of circumferentially spaced lobe portions with V-shaped crests and intervening chordal portions with truncated flat crests, the crests of said lobes on the longitudinal body embodying sectors of a circle defined by equal radii centered on the tap longitudinal axis and the truncated flat crests of the intervening chordal portions being equidistantly spaced from said longitudinal axis, merging into the V-shaped crests of the leading and trailing parts of the lobe portions at either end thereof and presenting elongated lenticular configurations in plan therebetween, the root of the thread turns on either side of the lobes being relieved along radially decreasing arcs which merge into the root of the lobes.
Claim 2
Dependent Claim
155 words
A tap comprising a longitudinal body of generally polygonal shape in cross section having a tapered end and a thread helically arranged about said body and tapered end, the turns of the thread on said longitudinal body being of constant size and shape and consisting of circumferentially spaced lobe portions with V-shaped crests and intervening chordal portions with truncated flat crests, the crests of said lobes on the longitudinal body embodying sectors of a circle defined by equal radii centered on the tap longitudinal axis and the truncated flat crests of the intervening chordal portions being equidistantly spaced from said longitudinal axis, merging into the V-shaped crests of the leading and trailing parts of the lobe portions at either end thereof and presenting elongated lenticular configurations in plan therebetween, the root of the thread turns on either side of the lobes being relieved along radially decreasing arcs which merge into the root of the lobes.
Claim 3
Dependent Claim
23 words
A tap as claimed in claim 1 wherein the V-shaped crests of the spaced lobe portions correspond to the American National thread form.
Claim 4
Dependent Claim
24 words
A tap as claimed in claim 1 wherein the lobe portions have concentric crests and root sectors centered on the axis of the tap.
Claim 5
Dependent Claim
24 words
A tap as claimed in claim 3 wherein the concen-tric root sectors of the lobes are of greater angular extent than their concentric crests.
Claim 6
Dependent Claim
21 words
A tap as claimed in claim 1 wherein the truncated crest of each chordal portion of the thread is generally planar.
Claim 7
Dependent Claim
31 words
A tap as claimed in claim 1 wherein the thread turns on the longitudinal body have at least three V-shaped crested lobe portions and a corresponding number of intervening chordal portions.
Claim 8
Dependent Claim
31 words
A tap as claimed in claim 6 wherein the longitudinal body has a generally pyramidal shaped tapered entrant end and the starting turn of the thread thereon has a sharp V-crest.
Claim 9
Dependent Claim
49 words
A tap as claimed in claim 1 wherein the longitudinal body has at least four equi-dimensional sides, said sides being separated by rounded corners which comprise said lobe portions of the thread turns and are centered on the longitudinal axis of the tap and equi-distantly spaced from said axis.
Claim 10
Dependent Claim
15 words
A tap as claimed in claim 8 further having a generally pyramidal tapered entrant end.
Claim 11
Dependent Claim
23 words
A tap as claimed in claim 9 wherein at least the first thread on said tapered entrant end has a sharp V-shaped crest.
Claim 12
Dependent Claim
35 words
A tap as claimed in claim 10 wherein at least the last turn of the thread on said tapered entrant end has circumferentially spaced chordal portions with truncated crests between arcuate portions with sharp V-crests.
Claim 13
Dependent Claim
19 words
A tap as claimed in claim 1 further having a supporting shank at one end of said threaded body.
Claim 14
Dependent Claim
23 words
A tap as claimed in claim 12 wherein the thread on the body of the tap is continuous into the tapered end thereof.
Claim 15
Dependent Claim
24 words
A tap as claimed in claim 12 wherein the first turns of the thread on the tapered end thereof have a continuous V-shaped crest.
Claim 16
Dependent Claim
64 words
A tap as claimed in claim 1 wherein at least the turn of the thread on the tapered entrant end immEdiately adjacent the tap body has circumferentially spaced arcuate portions with the V-shaped crests and intervening chordal portions with truncated crests presenting an elongated lenticular configuration, said arcuate and chordal portions being aligned with corresponding portions on the thread turns of the tap body.
Claim 17
Dependent Claim
26 words
A tap as claimed in claim 15 wherein the first turns of the thread on the tapered entrant end of the tap have a V-shaped crest.
Claim 18
Dependent Claim
27 words
A tap as claimed in claim 1 wherein the lobe crests of each thread turn have a much shorter angular extent that do the intervening chordal portions.
Claim 19
Dependent Claim
24 words
A tap as claimed in claim 17 wherein the lobe crests of each thread turn have a total angular extent of less than 60*.
Claim 20
Dependent Claim
28 words
A tap as claimed in claim 1 wherein the radial relief of the root of the chordal portions continues to a maximum low point midway between adjacent lobes.
Claim 21
Dependent Claim
40 words
A tap as claimed in claim 1 wherein the thread turns on the tapered end of the tap are of a similar polygonal shape to those on the longitudinal body but regularly decreasing in diameter from the constant size thereof.
Claim 22
Dependent Claim
52 words
A tap as claimed in claim 20 wherein the thread turns on the tapered end of the tap have circumferentially spaced lobes with intervening chordal portions of reduced radial height, said lobes on the tapered end having knife edge V-shaped crests comprising sectors of a circle centered on the tap longitudinal axis.
Claim 23
Dependent Claim
23 words
A tap as claimed in claim 21 wherein the lobes of the thread turns on the tapered end have concentric root and crest.
Claim 24
Dependent Claim
26 words
A tap as claimed in claim 22 wherein the crest and root of the thread turns between the lobes on the tapered end are radially relieved.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-03 | 1977-06-04 | 1977-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-03 | 1981-06-04 | 1981-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-03 | 1985-06-04 | 1985-12-04 | $7700.00 | Window Closed / Lapsed |