US4010807A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tool for forming a hole for a fastening element
Assignee: FISCHER-WERKE ARTUR FISHER & Co KG D-7244 TUMLINGGEN/WALDACHTAL GERMANY GmbH
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Filing: 1974-10-02
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Granted: 1977-03-08
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Expires: 1994-10-02
Abstract
Abstract A substantially cylindrical hole is drilled into a support structure, and the end of the hole remote from the point of entry of the drilling tool into the structure is enlarged in its cross-sectional area so as to provide abutment surfaces for spreading portions of a fastening element inserted into the hole subsequently to the drilling thereof. The drilling tool includes a drill shaft, and a drill bit connected to the free end of the drill shaft and having lateral cutting edges. The cutting edges may diverge in direction axially away from the drill shaft and a collar may be provided on the drill shaft which, in cooperation with the inner surface bounding the hole forms a fulcrum for a lever-type angular displacement of the drilling tool for increasing the cross-sectional area of the remote end of the hole. The collar may be mounted on the drill shaft for displacement between a plurality of axially spaced positions and for arresting in any one of these positions so as to adjust the drilling tool to a particular depth of the hole to be drilled.
Inventors
- 👤 Athur Fischer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:25
CPC Classifications
B; B23; B23B; B23B51/00; B23B51/0018; B23B51/0027; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49826; Y10T29/49908; Y10T29/49938; Y10T408/00; Y10T408/55; Y10T408/557; Y10T408/558; Y10T408/5583; Y10T408/5586; Y10T408/89; Y10T408/892; Y10T408/8925
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
146 words
A tool for drilling undercut holes in a stationary support structure comprising, in combination, an elongated drill shaft having an axis of rotation; a drill bit at one end of said drill shaft and having cutting edges located radially outwardly of said drill shaft, said cutting edges being operative for removing material from the stationary support structure to initially form a cylindrical hole therein; and means axially adjustably fixed to said drill shaft for supporting said drill shaft and pivoting the latter out of axial coincidence with the cylindrical hole about a fulcrum located adjacent an inlet end of the hole whereby said cutting edges remove material from the support structure beyond the confines of the cylindrical hole in a region thereof remote from the inlet end to thereby increase the cross-sectional area of the hole in such region at a selected distance from said fulcrum.
Claim 2
Dependent Claim
146 words
A tool for drilling undercut holes in a stationary support structure comprising, in combination, an elongated drill shaft having an axis of rotation; a drill bit at one end of said drill shaft and having cutting edges located radially outwardly of said drill shaft, said cutting edges being operative for removing material from the stationary support structure to initially form a cylindrical hole therein; and means axially adjustably fixed to said drill shaft for supporting said drill shaft and pivoting the latter out of axial coincidence with the cylindrical hole about a fulcrum located adjacent an inlet end of the hole whereby said cutting edges remove material from the support structure beyond the confines of the cylindrical hole in a region thereof remote from the inlet end to thereby increase the cross-sectional area of the hole in such region at a selected distance from said fulcrum.
Claim 3
Dependent Claim
20 words
A tool as defined in claim 1, wherein said cutting edges diverge in direction axially away from said drill shaft.
Claim 4
Dependent Claim
27 words
A tool as defined in claim 1, wherein said drill bit is a drill leaf extending substantially radially of said axis and provided with said cutting edges.
Claim 5
Dependent Claim
18 words
A tool as defined in claim 1 said supporting means comprising a collar connected to said drill shaft.
Claim 6
Dependent Claim
29 words
A tool as defined in claim 4, wherein the contour of said collar is part-circular at least in the region of contact of said collar with the support structure.
Claim 7
Dependent Claim
191 words
A tool for drilling undercut holes in stationary support structure for anchoring therein fastening elements having spreading portions of a predetermined length, comprising in combination, an elongated drill shaft having an axis of rotation; a drill bit at one end of said drill shaft and having cutting edges located radially outwardly of said drill shaft, at least one of said cutting edges having a length at least corresponding to said predetermined length, said cutting edges being operative for removing material from the stationary support structure to initially form a cylindrical hole therein; and means axially adjustably fixed to said drill shaft for supporting said drill shaft and pivoting the latter out of axial coincidence with the cylindrical hole about a fulcrum located adjacent an inlet end of the hole whereby said cutting edges remove material from support structure beyond the confines of the cylindrical hole in a region thereof remote from the inlet end to thereby increase the cross-sectional area of the hole in such region and provide undercut abutment surfaces for engagement by the spreading portions of the fastening element in such region at a selected distance from said fulcrum.
Claim 8
Dependent Claim
191 words
A tool for drilling undercut holes in stationary support structure for anchoring therein fastening elements having spreading portions of a predetermined length, comprising in combination, an elongated drill shaft having an axis of rotation; a drill bit at one end of said drill shaft and having cutting edges located radially outwardly of said drill shaft, at least one of said cutting edges having a length at least corresponding to said predetermined length, said cutting edges being operative for removing material from the stationary support structure to initially form a cylindrical hole therein; and means axially adjustably fixed to said drill shaft for supporting said drill shaft and pivoting the latter out of axial coincidence with the cylindrical hole about a fulcrum located adjacent an inlet end of the hole whereby said cutting edges remove material from support structure beyond the confines of the cylindrical hole in a region thereof remote from the inlet end to thereby increase the cross-sectional area of the hole in such region and provide undercut abutment surfaces for engagement by the spreading portions of the fastening element in such region at a selected distance from said fulcrum.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-03-07 | 1980-09-06 | 1981-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-07 | 1984-09-06 | 1985-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-07 | 1988-09-06 | 1989-03-08 | $7700.00 | Window Closed / Lapsed |