Patent US2586822A successfully refreshed from Google Patents.
Patent CA1097104A successfully refreshed from Google Patents.
CA1097104A
Expired / Lapsed
CA
⏱️ 0.0 years remaining
Drills
Assignee: Somta Tools Pty Ltd
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Filing: 1979-01-19
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Granted: 1981-03-10
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Expires: 1999-01-19
Abstract
Abstract A B S T R A C T The invention provides a twist drill particularly suitable for drilling holes in wooden railway sleepers. The drill comprises a fluted body terminating at its leading end in opposed cutting faces, a threaded portion trailing the cutting faces and adapted to serve a drill feeding function, and a second set of opposed cutting faces which trail the threaded portion and which have a larger radius of cut than the leading cutting faces. Preferably the second set of cutting faces are of sub-stantially the same diameter as that of the body.
Inventors
- 👤 Keith Siddall
- 👤 Kenneth A. Steele
- 👤 Robert A. Poole
Bibliographic Details
Application Number
—
Jurisdiction
CA
Data Source
google_patents
Last Synchronized
2026-10-30 08:44
CPC Classifications
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Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
69 words
A drill or the like comprising a shank or body providing a first lateral cutting edge at its leading end, material engaging means trailing the first cutting edge and adapted in use to engage material to be drilled to advance the drill into the material, and a second lateral chisel-like cutting edge trailing the material engaging means and having a greater radius of cut than the first cutting edge.
Claim 2
Dependent Claim
69 words
A drill or the like comprising a shank or body providing a first lateral cutting edge at its leading end, material engaging means trailing the first cutting edge and adapted in use to engage material to be drilled to advance the drill into the material, and a second lateral chisel-like cutting edge trailing the material engaging means and having a greater radius of cut than the first cutting edge.
Claim 3
Dependent Claim
21 words
The drill according to claim 1 wherein each of the cutting edges comprises a pair of diametrically opposed chisel-like cutting faces.
Claim 4
Dependent Claim
30 words
The drill according to claim 1 wherein the ratio between the radius of cut of the first cutting edge and that of the second cutting edge is greater than 0,3.
Claim 5
Dependent Claim
11 words
The drill according to claim 3 wherein the ratio is 0,7.
Claim 6
Dependent Claim
18 words
The drill according to claim 1 wherein the material engaging means is a screw thread or the like.
Claim 7
Dependent Claim
82 words
The drill according to claim 1 wherein the shank or body defines substantially helical flutes and lands, with the tip of the shank providing a pair of opposed cutting faces having a smaller cutting diameter than the land diameter, the lands being undercut and threaded to the rear of the cutting faces, with the web of the lands at the end of the undercut portion defining a second set of cutting faces, having a cutting diameter substantially equal to the land diameter.
Claim 8
Dependent Claim
47 words
The drill according to claim 6 wherein the lands to the rear of the second set of cutting faces are provided with. one or more laterally extending reaming formations designed to ream a hole being drilled to a greater diameter than the land diameter, for clearance purposes.
Claim 9
Dependent Claim
17 words
The drill according to claim 6 wherein the threaded lands or sub-lands are disposed within the flutes.
Claim 10
Dependent Claim
49 words
The drill according to claim 5 wherein the screw thread is a multiple thread starting at the first pair of cutting faces, so that more than one circumferentially spaced cutting corner is provided at the outer extremity of each cutting face by the by the starts of the threads.
Claim 11
Dependent Claim
44 words
The drill according to claim 5 wherein the thread is of a buttress form adapted to provide a cutting corner at the outer region of the leading cutting faces, such cutting corner forming an acute angle relative to the remainder of the cutting face.
References Cited (Backward Citations)
No citation records indexed.
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