SG173080A1 - Self drilling screw - Google Patents
Self drilling screw Download PDFInfo
- Publication number
- SG173080A1 SG173080A1 SG2011052644A SG2011052644A SG173080A1 SG 173080 A1 SG173080 A1 SG 173080A1 SG 2011052644 A SG2011052644 A SG 2011052644A SG 2011052644 A SG2011052644 A SG 2011052644A SG 173080 A1 SG173080 A1 SG 173080A1
- Authority
- SG
- Singapore
- Prior art keywords
- thread
- screw
- drill portion
- threaded shank
- drill
- Prior art date
Links
- 238000005553 drilling Methods 0.000 title abstract description 9
- 239000002184 metal Substances 0.000 claims abstract description 24
- 229910052751 metal Inorganic materials 0.000 claims abstract description 24
- 238000005253 cladding Methods 0.000 claims abstract description 7
- 239000002023 wood Substances 0.000 claims abstract description 6
- 238000005520 cutting process Methods 0.000 claims description 12
- 239000000463 material Substances 0.000 claims description 5
- 230000000630 rising effect Effects 0.000 claims description 5
- 229910000831 Steel Inorganic materials 0.000 abstract description 7
- 239000010959 steel Substances 0.000 abstract description 7
- 230000000694 effects Effects 0.000 abstract description 4
- 239000011121 hardwood Substances 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 238000007689 inspection Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 235000008331 Pinus X rigitaeda Nutrition 0.000 description 1
- 235000011613 Pinus brutia Nutrition 0.000 description 1
- 241000018646 Pinus brutia Species 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009435 building construction Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B25/00—Screws that cut thread in the body into which they are screwed, e.g. wood screws
- F16B25/10—Screws performing an additional function to thread-forming, e.g. drill screws or self-piercing screws
- F16B25/103—Screws performing an additional function to thread-forming, e.g. drill screws or self-piercing screws by means of a drilling screw-point, i.e. with a cutting and material removing action
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B25/00—Screws that cut thread in the body into which they are screwed, e.g. wood screws
- F16B25/001—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by the material of the body into which the screw is screwed
- F16B25/0031—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by the material of the body into which the screw is screwed the screw being designed to be screwed into different materials, e.g. a layered structure or through metallic and wooden parts
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B25/00—Screws that cut thread in the body into which they are screwed, e.g. wood screws
- F16B25/0036—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by geometric details of the screw
- F16B25/0042—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by geometric details of the screw characterised by the geometry of the thread, the thread being a ridge wrapped around the shaft of the screw
- F16B25/0047—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by geometric details of the screw characterised by the geometry of the thread, the thread being a ridge wrapped around the shaft of the screw the ridge being characterised by its cross-section in the plane of the shaft axis
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Geometry (AREA)
- Connection Of Plates (AREA)
- Joining Of Building Structures In Genera (AREA)
- Roof Covering Using Slabs Or Stiff Sheets (AREA)
Abstract
A self-drilling screw for fastening sheet metal roofing or other cladding to wood or metal, has a buttress thread in which the trailing flank of the thread is inclined at a greater angle to the axis of the screw shank than is the leading flank. The thread crest is sharp with a width of no more than substantially 0.25mm which enables the thread to tap into all timbers ranging from soft to ultra hard. The thread form also enables the thread to drive into thick steel battens while retaining good pull-out strength when driven into thin metal battens due to the effect of the buttress thread.
Description
SELF DRILLING SCREW
1) Field of the Invention
The present invention relates to a self drilling screw for fixing metal roof sheeting or other cladding to a range of different substrates. 2) Description of the Invention
Type 17 self drilling screws, which have been widely available for many years, are primarily timber screws for fixing into soft and hard timber. While Type 17 screws are sometimes used to fix metal roof sheeting to underlying timber battens, the drilling tip of the screw has difficulty in penetrating the metal sheeting and sometimes fails to do so. Accordingly, while fastening of roof sheeting in this way using the Type 17 screws can be achieved, nevertheless it is quite time consuming and can result in substantial wastage of screws which were unable to properly penetrate the sheeting. Type 17 screws are not, however, suitable for fastening metal roof sheeting to steel battens without pre-drilling and alternative screws are available for that purpose. Screws are also currently available for driving into both timber and steel battens but tend to be limited as to the thickness of steel batten into which they can be driven; moreover, although these screws tend to have good performance when driving into relatively soft timbers, pine for example, they are not suitable for use into hard timbers.
The present invention relates to a self drilling screw having improved versatility for fixing metal roof sheeting and other cladding to a wider range of materials including both thin and thick steel battens and timber from soft to very hard.
According to the present invention there is provided a screw for fastening sheet metal roofing material or other cladding to a support of wood or metal, the screw having a drill portion at its forward end and a threaded shank portion rearwardly of the drill portion, the drill portion having opposed cutting edges at its outer end and flutes extending generally axially rearwardly from the cutting edges, the threaded shank portion being formed with a sharp thread (as herein defined) commencing at the end of the drill portion remote from the cutting edges and rising progressively over a plurality of turns to full thread height, the drill portion being of a substantially constant diameter inwardly of the cutting edges and the root diameter of the threaded shank portion being of substantially constant diameter which is substantially the same as that of the drill portion, the thread being a buttress thread in which the trailing flank of the thread is inclined at a greater angle to the axis of the shank than is the leading flank.
By "sharp thread" there is meant a thread having a crest which when considered in transverse cross-section has a width of no more than substantially 0.25mm. In this respect, although on casual inspection many thread forms may seem to terminate ina sharply pointed crest, detailed inspection will usually reveal that not to be the case.
In current forms of roofing screw the thread crest tends to be flattened or rounded rather than pointed with a width in transverse cross-section typically of the order of 0.75 to 1.00mm. A crest of that form cannot act in the manner of a sharp thread to produce the effects described in detail herein.
In a preferred embodiment of the invention the trailing flank of the thread is inclined to the axis of the shank at an angle of from substantially 70 to 85°, an inclination of around 75° being especially preferred.
Advantageously the thread pitch of the screw is 10tpi (turns per inch) to 13tpi, with 12tpi being especially preferred.
Further according to the invention, there is provided a screw for fastening sheet metal roofing material or other cladding to a support of wood or metal, the screw having a drill portion at its forward end and a threaded shank portion rearwardly of the drill portion, the threaded shank portion being formed with a sharp thread of which the crest has a width of no more than substantially 0.25mm, the thread rising progressively over a plurality of turns to full thread height, the root diameter of the threaded shank portion being of substantially constant diameter which is substantially the same as the diameter of the drill portion, wherein the thread is a buttress thread in which the trailing flank of the thread is inclined at a greater angle to the axis of the shank than is the leading flank, and the pitch of the thread is 10 to 13tpi.
An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which:
Figure 1 is a side view of a screw in accordance with the invention;
Figure 2 is an enlarged detail of zone A in Figure 1;
Figure 3 is an enlarged detail of zone B in Figure 2; and
Figure 4 is a schematic cross-section through the thread.
The screw shown in the accompanying drawings comprises a driving head 2 at one end, a drill portion 4 at the other end and a threaded shank portion 6 of constant root diameter extending from the inner end of the drill portion 4. Although as shown, the head 2 has a conventional hexagonal driving formation, the head may be of other configuration. The drill portion 4 has at its outer end inclined cutting edges 8 and a pair of flutes 10 intersecting the cutting edges and extending generally axially into the threaded shank portion 6. Apart from its outer end at which the cutting edges 8 are formed, the drill portion 4 is of constant diameter throughout its length. The thread commences at the end of the drill portion 4 remote from the cutting edges 8 and rises progressively to maximum height over several turns, three to four turns in the preferred embodiment.
The root diameter of the threads in the threaded shank portion 6 is substantially the same as the diameter of the drill portion 4. While the diameter of the two may be exactly the same, as a result of manufacturing tolerances and different manufacturing processes needed to produce the drill portion and the threaded portion (processes which are well known per se) slight variation may arise between the diameter of these two portions; that variation may be of the order of plus or minus 0.15mm and a difference of that order will not adversely effect the performance of the screw.
Accordingly, the reference herein to the diameters of the thread root and drill portion being substantially the same is intended to encompass the possibility of slight variation between the two.
In use, when driving into a steel or timber batten or other substrate, the drill portion 4 bores a hole with swarf being cleared from the hole via the flutes 10. As the root diameter of the thread is substantially the same as that of the hole formed by the drill portion, the progressively rising thread will engage and tap the hole over the entire thread height.
The screw of the preferred embodiment is designed for use into all timbers ranging from soft to ultra hard, for thin gauge metal up to 1.2mm and for thicker metal up to 1.9mm. An important factor in achieving this versatility is the design of the thread.
The thread itself is a sharp thread (as previously defined) thereby providing what will be termed as a sharp crest. The sharp crest is important because as the drill portion drills into the substrate the tapered thread progressively taps into the wall of the hole and the sharpness of its crest enables this action to occur even in ultra hard timbers.
The performance of ultra hard timbers in this respect is more like metal and the action which has been described here also takes place when driving into thick steel battens, an action likewise enabled by the sharpness of the thread crest.
The thread is also of buttress type in which the trailing flank 12 of the thread (the flank facing the head end) is inclined at a greater angle to the axis x-x of the screw than is the leading flank 14 (the flank facing the drilling end); this is shown in Figure 4. The use of a buttress thread is important because it provides good resistance to pullout when driven into thin gauge metal battens. This effect is described in our prior Australian patent 729658 and this is effective even under cyclonic loading as discussed in that patent. Whereas the screw described in that patent was specifically designed for driving into thin metal battens, the screw of the preferred embodiment is designed for a much wider range of uses and the buttress thread is subject to rather different design considerations. Whereas the angle o of the leading flank 14 is substantially 60° (a broadly conventional angle), the angle B of the trailing flank 12 is from 70 to 85°, preferably around 75°. A trailing flank angle in that range while still of a magnitude which provides good pullout strength in thin gauge metal provides added strength to the thread so that the thread will not deform under load and will give increased holding strength when driven into hard timbers and thicker metals.
The thread pitch itself is an important factor in the performance of the screw when driven into hard timbers. Screws of the type under consideration for use in building construction are usually 13 to 15 gauge. The thread pitch of the screw of the preferred embodiment is 10tpi to 13tpi (turns per inch). With a pitch of that order, when the thread taps into hard wood an adequate volume of wood remains between adjacent threads to provide the required anchorage and hence the high pullout strength associated with the hard wood. Although tests have indicated that thread forms of either 10tpi or 13tpi are effective when used with hard wood, 12tpi is preferred as it has been determined that this provides better performance when the screw is used with thin metal battens.
The embodiment has been described by way of example only and modifications are possible within the scope of the invention.
Claims (6)
1. A screw for fastening sheet metal roofing material or other cladding to a support of wood or metal, the screw having a drill portion at its forward end and a threaded shank portion rearwardly of the drill portion, the drill portion having opposed cutting edges at its outer end and flutes extending generally axially rearwardly from the cutting edges, the threaded shank portion being formed with a sharp thread (as herein defined) commencing at the end of the drill portion remote from the cutting edges and rising progressively over a plurality of turns to full thread height, the drill portion being of a substantially constant diameter inwardly of the cutting edges and the root diameter of the threaded shank portion being of substantially constant diameter which is substantially the same as that of the drill portion, the thread being a buttress thread in which the trailing flank of the thread is inclined at a greater angle to the axis of the shank than is the leading flank.
2. A screw according to claim 1, wherein the trailing flank of the thread is inclined to the axis of the shank at an angle of from substantially 70 to 85°.
3. A screw according to claim 2, wherein the inclination of the trailing flank is substantially 75 °.
4. A screw according to claim 2, wherein the thread pitch is 10 to 13tpi.
5. A screw according to claim 4, wherein the thread pitch is 12tpi.
6. A screw for fastening sheet metal roofing material or other cladding to a support of wood or metal, the screw having a drill portion at its forward end and a threaded shank portion rearwardly of the drill portion, the threaded shank portion being formed with a sharp thread of which the crest has a width of no more than substantially 0.25mm, the thread rising progressively over a plurality of turns to full thread height, the root diameter of the threaded shank portion being of substantially constant diameter which is substantially the same as the diameter of the drill portion, wherein the thread is a buttress thread in which the trailing flank of the thread is inclined at a greater angle to the axis of the shank than is the leading flank, and the pitch of the thread is 10 to 13tpi.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2009900229A AU2009900229A0 (en) | 2009-01-21 | Self drilling screw | |
PCT/IB2010/050272 WO2010084469A1 (en) | 2009-01-21 | 2010-01-21 | Self drilling screw |
Publications (1)
Publication Number | Publication Date |
---|---|
SG173080A1 true SG173080A1 (en) | 2011-08-29 |
Family
ID=42355588
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
SG2011052644A SG173080A1 (en) | 2009-01-21 | 2010-01-21 | Self drilling screw |
SG2014004618A SG2014004618A (en) | 2009-01-21 | 2010-01-21 | Self drilling screw |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
SG2014004618A SG2014004618A (en) | 2009-01-21 | 2010-01-21 | Self drilling screw |
Country Status (4)
Country | Link |
---|---|
CN (1) | CN102333966B (en) |
AU (1) | AU2010200204B2 (en) |
SG (2) | SG173080A1 (en) |
WO (1) | WO2010084469A1 (en) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9091084B2 (en) * | 2011-09-20 | 2015-07-28 | Dissing A/S | Fastening of a corrugated sheet in a roof construction or wall construction |
US11105362B2 (en) | 2018-01-12 | 2021-08-31 | Triangle Fastener Corporation | Anti-burr threaded fastener |
IES87072B2 (en) * | 2018-02-27 | 2019-12-11 | Toolfast Ltd | A fixing means |
JP7086470B2 (en) * | 2018-05-18 | 2022-06-20 | 株式会社青山製作所 | Bolt and fastening structure |
CN110345144A (en) * | 2019-07-31 | 2019-10-18 | 嘉兴承泽五金有限公司 | A kind of segmented thread backing-up screw |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3965793A (en) * | 1971-12-08 | 1976-06-29 | Keystone Consolidated Industries, Inc. | Particleboard screw |
US4144795A (en) * | 1977-10-20 | 1979-03-20 | Gutshall Charles E | Long-pitch re-rolled crest thread |
US5947670A (en) * | 1996-09-20 | 1999-09-07 | Illinois Tool Works Inc. | Self-drilling fastener |
AUPO502997A0 (en) * | 1997-02-11 | 1997-03-06 | W.A. Deutscher Pty Ltd | Fastening screw and fastening system |
US6394726B1 (en) * | 2000-05-31 | 2002-05-28 | Illinois Tool Works Inc. | Threaded fastener |
JP2002039135A (en) * | 2000-07-24 | 2002-02-06 | Okitsu Rasen Kk | Screw for lightweight cellular concrete |
US6702537B2 (en) * | 2001-01-12 | 2004-03-09 | Illinois Tool Works Inc. | High profile thread forming screw |
US6494655B1 (en) * | 2001-09-13 | 2002-12-17 | Conti Fasteners Ag | Self-tapping screw and method for joining thin workpieces |
US6923611B2 (en) * | 2002-06-13 | 2005-08-02 | Illinois Tool Works Inc. | Self-drilling fastener |
US7682118B2 (en) * | 2007-04-19 | 2010-03-23 | Illinois Tool Works Inc. | Threaded screw fastener with multiple characteristic threads |
-
2010
- 2010-01-19 AU AU2010200204A patent/AU2010200204B2/en active Active
- 2010-01-21 SG SG2011052644A patent/SG173080A1/en unknown
- 2010-01-21 SG SG2014004618A patent/SG2014004618A/en unknown
- 2010-01-21 WO PCT/IB2010/050272 patent/WO2010084469A1/en active Application Filing
- 2010-01-21 CN CN201080008361.0A patent/CN102333966B/en active Active
Also Published As
Publication number | Publication date |
---|---|
CN102333966A (en) | 2012-01-25 |
WO2010084469A1 (en) | 2010-07-29 |
AU2010200204A1 (en) | 2010-08-05 |
CN102333966B (en) | 2015-07-29 |
AU2010200204B2 (en) | 2015-07-02 |
SG2014004618A (en) | 2014-03-28 |
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