US3795958A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gear tooth broach
Assignee: Nachi Machining Technology Co
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Filing: 1972-08-01
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Granted: 1974-03-12
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Expires: 1992-08-01
Abstract
Abstract A gear tooth broach for helical gears has the last few finishing teeth, which are adapted to engage in the work piece simultaneously, having one side thereof modified to prevent cutting and to serve as a guide to prevent drift of the broach which would produce a build-up referred to in the art as a ''''dog leg'''' lead.
Inventors
- 👤 J Psenka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:16
CPC Classifications
B; B23; B23F; B23F21/00; B23F21/26; Y; Y10; Y10T; Y10T407/00; Y10T407/16; Y10T407/1685; Y10T407/17
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
157 words
A helical broach for broaching helical teeth comprising an elongated device having a multiplicity of longitudinally helically extending series of teeth stepped to progressively cut a corresponding multiplicity of helically extending tooth spaces, all of said teeth except the last few having front faces and side surfaces intersecting the front faces to form side cutting edges, all of said teeth except the last few being of substantially full height and of progressively increasing width and provided with sharp relieved cutting edges at both sides to perform an operation known as full form finishing in which each tooth removes chips at opposite sides thereof for the full height of the tooth and of substantially equal thickness, only the last few teeth of the broach, not exceeding in number the maximum number of teeth in contact with a work piece for which the broach is designed, being modified to have one side thereof non-cutting and operable only as guides.
Claim 2
Dependent Claim
157 words
A helical broach for broaching helical teeth comprising an elongated device having a multiplicity of longitudinally helically extending series of teeth stepped to progressively cut a corresponding multiplicity of helically extending tooth spaces, all of said teeth except the last few having front faces and side surfaces intersecting the front faces to form side cutting edges, all of said teeth except the last few being of substantially full height and of progressively increasing width and provided with sharp relieved cutting edges at both sides to perform an operation known as full form finishing in which each tooth removes chips at opposite sides thereof for the full height of the tooth and of substantially equal thickness, only the last few teeth of the broach, not exceeding in number the maximum number of teeth in contact with a work piece for which the broach is designed, being modified to have one side thereof non-cutting and operable only as guides.
Claim 3
Dependent Claim
64 words
A broach as defined in claim 1 in which the front faces of said teeth are generally perpendicular to the axis of said broach, so as to form acute and obtuse included angle cutting edges at opposite sides thereof, and in which the modification of the last few teeth is to render the acute included angle sides thereof non-cutting and operable only as guides.
Claim 4
Dependent Claim
56 words
A broach as defined in claim 1 in which the teeth of said series are of a height corresponding substantially to full depth of the tooth space, so that each tooth, except for the few modified teeth at the trailing end of the broach, are adapted to shave the work gear teeth throughout its full height.
Claim 5
Dependent Claim
22 words
A broach as defined in claim 3 in which said multiplicity of teeth are formed on the exterior of a tubular shell.
Claim 6
Dependent Claim
24 words
A broach as defined in claim 3 in which the modified teeth have no back-off at the side having the acute included angle corner.
Claim 7
Dependent Claim
41 words
A broach as defined in claim 3 in which the modified teeth have the corner defined by the intersection between the side of the teeth and the front face thereof at the normally acute angled side being dubbed off or dulled.
Claim 8
Dependent Claim
64 words
A broach as defined in claim 3, in which each of the modified teeth has one side thereof inclined rearwardly and outwardly to a point adjacent to but spaced slightly forwardly of the rear end of the teeth to provide guide surfaces on the teeth near the rear end and to provide clearance between the front corner and the side of the tooth space.
Claim 9
Dependent Claim
24 words
A broach as defined in claim 4 in which the modified teeth have no back-off at the side having the acute included angle corner.
Claim 10
Dependent Claim
41 words
A broach as defined in claim 4 in which the modified teeth have the corner defined by the intersection between the side of the teeth and the front face thereof at the normally acute angled side being dubbed off or dulled.
Claim 11
Dependent Claim
56 words
A broach as defined in claim 4, the side thereof incLined rearwardly and outwardly to a point adjacent to but spaced slightly forwardly of the rear end of the teeth to provide guide surfaces on the teeth near the rear end and to provide clearance between the front corner and the side of the tooth space.
Claim 12
Dependent Claim
83 words
A broach as defined in claim 1 in which the teeth are also arranged in one or more helical paths around the broach, in which the front face of said teeth are generally perpendicular to said helical paths, and in which the modification of the last few teeth is to form the sides thereof whose cutting edges are located axially ahead of the other sides thereof as guide surfaces to ensure cutting a true lead by the cutting edges at said other sides.
References Cited (Backward Citations)
US2898670A
Cited
US3178800A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-11 | 1977-09-10 | 1978-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-11 | 1981-09-10 | 1982-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-11 | 1985-09-10 | 1986-03-12 | $7700.00 | Window Closed / Lapsed |