CA1275840C - Drill screw - Google Patents
Drill screwInfo
- Publication number
- CA1275840C CA1275840C CA000515903A CA515903A CA1275840C CA 1275840 C CA1275840 C CA 1275840C CA 000515903 A CA000515903 A CA 000515903A CA 515903 A CA515903 A CA 515903A CA 1275840 C CA1275840 C CA 1275840C
- Authority
- CA
- Canada
- Prior art keywords
- fastener
- pilot end
- minor axis
- cutting
- pair
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000005520 cutting process Methods 0.000 claims abstract description 27
- 238000005553 drilling Methods 0.000 claims abstract description 24
- 238000005242 forging Methods 0.000 description 16
- 239000000463 material Substances 0.000 description 13
- 238000004519 manufacturing process Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 230000002093 peripheral effect Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 230000002028 premature Effects 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 229910000677 High-carbon steel Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000009172 bursting Effects 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 229910001256 stainless steel alloy Inorganic materials 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
- F16B25/0036—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by geometric details of the screw
- F16B25/0084—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 geometric details of the tip
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Geometry (AREA)
- Forging (AREA)
- Supporting Of Heads In Record-Carrier Devices (AREA)
- Iron Core Of Rotating Electric Machines (AREA)
- Dowels (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A drilling and thread forming fastener is provided having a pilot end with a cutting tip and a pair of flutes formed thereon.
The flutes define the length of the pilot end, which is tapered in one direction only over the greater portion of its extent.
A drilling and thread forming fastener is provided having a pilot end with a cutting tip and a pair of flutes formed thereon.
The flutes define the length of the pilot end, which is tapered in one direction only over the greater portion of its extent.
Description
~ 7 ~
BACKGROUND OF THE INVENTION
The present invention relates to a rotary threaded fastener of the self-drilling and threading type, and more particularly to a fastener of that type which is manufactured by a pair of forging dies.
Various threaded fasteners of the self-drilling and thread forming type are known in the art, some of which are particularly adopted for manufacture by a milling process, while others are manufactured by a forging process which employs a pair of matched dies. A typical example of the type oF drilling and thread forming Fastener which is preferably formed by the forging process is shown in U.S. Patent No. 3395603, issued August 6, 1968 to E.J. Skierski and assigned to khe assi~nee of the present invention. Fasteners manufactured in accorclance with the teachings of this patent have met with wide acceptance as they provide a fastener which is simple to use, requiring no pre-drilling of the structure to which it is assembled, and fasteners of this type have proven to be easy to manufacture by mass production methods.
Recently, however, there has been a demand for self-drilling fasteners to be manufactured from high carbon steel, stainless steel, or metallic alloys which are of a hardness exceeding those of normal requirements. In some instances, it has been found that the ~2~8~
forging dies employed to manufacture a drill point on these fasteners is susceptible to premature breakage, when these harder materials are employed. It is considered that the stresses inherent in present point forging die configurations trap the harder material of the headed blank being worked on during the point forging operation, and that the entrapment of the blank material and its subsequent cold flow generates excessive stresses in the point forging die, causing in some instances, a premature point forging die breakage.
With the wide use of the self-drilllng and thread forming fasteners there has also been a requirement for the reduction in drilling time of the fastener. While existing point configurations which contain two flutes provide a satisfactory drill time in most applications, it is considered tilat they do not have sufficient clearance for chip flow to remove drilled material from the resultant hole, and thus to reduce drilling time. This occurs particularly when multi-layered assemblies of similar and dissimilar materials are operated upon . Such failure to remove drilled material can result in binding between the point and drilled hole surface causing excessive heat generation and resultant slower drill times.
The present invention therefore has as an object to provide a drilling and thread forming fastener of the type manufactured by a die forging process, which is effective to facilitate an increase in point forging die life.
Another object of the present invention is to provide a drilling and thread for~ling fastener wherein a greater clearance for escape of drilling chips is provided in the resultant drilled hole, during the dril1ing process.
Another object of the present invention is to provide a drilling and thread forming fastener which is susceptible to a reduction in drilling time over those drilling and thread fornning fasteners of the prior art.
~27~8~
SUMMARY OF THE INVENTION
The aforementioned objects and other objectives which will become apparent as the description proceeds are accomplished by providing a drilling and thread forming fastener having a threaded shank and a pilot end wherein the pilot end has a transverse major axis and a transverse minor axis intersecting at the center line of the fastener. A pair of flutes extending longitudinally over the pilot end serve to form a pair of cutting surfaces, in cross-section defining the major axis. A pair of lands concentric with the center line of the shank are each formecl of an arcuate surface extending outwardly to define the minor axis at its radial extent on any cross section of the pilot end. A substantially wedged shaped cuttiny tip is formed at the ternlinal portion of the pilot end. The minor axis increases in a linear progression from adjacent the cutting tip to a point remote from the cutting tip to thereby form an angular portion of said pilot end which longitudinal outer surface defines an angle with the fastener center line.
In a more detailed sense, the cutting surfaces are formed substantially parallel to one another over a greater portion of the pilot end angular portion.
h pair of mating dies are also provided for forming the above described structure in a forged pointing process, the inner surface ~;~75~
of the dies substantially conforming to the confi~uration set forth above.
~275~
BRIEF DESCRIPTION OF THE DRAWINGS
Reference is made to the accompanying drawing in which there is shown an illustrative embodiment of the invention from which its novel features and advantages will be apparent wherein FIG. 1 is a fragmentary elevational view showing a portion of a drilling and thread forming fastener constructed in accordance with the teachings of the subject invention;
FIG. 2 is an elevational view showing the fastener portion of FIG. 1 rotated through 90;
FIG. 3 is an encl view showing further details of the fastener of FTGS. 1 and 2;
FlG. 4 is a sectional view taken along the lines IV-IV of FIG.
3 showing details of the outer peripheral configuration of the fastener of FIGS. 1 though 3 at that section;
FIG. 5 is a sectional view taken along the lines V-V of FIG. 3 showing details of the outer peripheral configuration at that section;
FIG. 6 is a sectional view taken along the lines IV-IV of FIG.
3 shohing details of the outer peripheral configuration of the fastener of FIGS. 1 through 3 at that section, ~2~751 341) FIG. 7 is an elevational view similar to FIG. 2 showing the entire fastener of FIGS. 1 through 3 during the drilling operation;
FIG. 8 is a fragmentary elevational view similar to FIG. 1 showing the fastener of FIG. 7 rotated through 90 during the drilling operation;
FIG. 9 is a fragmentary elevational view showing an alternate embodiment of the structure of FIGS. 7 and 8; and FIG. 10 is a perspective view showing one of a pair of dies which comprise the d;e set for manufacture of the fastener shown in FIGS. 1 through 9.
~275~
DESCRIPTION OF A PREFERRED EMBODlMENT
Referring now to the drawings, and in particular to Figures I
through 3, there is shown a dril1ing and threaded forming fastener 10 having a shank 12 bearing the continuous thread 14 and a pilot end 16. The fastener 10 is substantially symmetrical about the center line oF the shank 12 and has a transverse major axis XX and a transverse minor axis YY intersecting at the center line. A pair of flutes 18 and 20 are formed in the pilot end 16 and extend longitudinally over the length of the pilot end to form a pa-,r of cutting surfaces 22, 24 extending along the major ax;s and in general defining the extent of the major axis of the fastener at any section thereof.
Each of the cutting surfaces 22 and 24 defines a cutting edge 26, 28 running substantially parallel to the center line of the fastener and terminating in an angular portion 30, 32. Each oF the angular portions 30 and 32 of the cutting edge terminates at a wedge shaped cutting tip 34. The cutting tip is disposed for preliminary entry into the metal surface to provide a lead for the cutting edges 30, 32, 26 and 28.
A pair of arcuate surfaces 36 and 38 extend along the length of the pilot end and terminate at an angular surface 40 and 42, ~L~7 5 ~34L~9 respectively, which extend toward the center line of the fastener to join the cutting tip 34.
Referring now to Figures 4 through 6 it will be noted that as the cross section of the pilot end 16 progresses from the cutting tip 34 to the threaded shank 12, the major axis remains substantially constant while the minor axis increases, approaching the length of the major axis but remaining less throughout the length of the pilot end.
The taper of the pilot end 16 is considered to extend from the minimum dinlension M as shown in Figures 2 and 3, to a maximum dimension W which is slightly less than the dimension of the X-X
axis at that point. The minimum dimension M is in the range of 20%
to 50, of the dimension W, and the taper generally extends over a length L which is in the range between 75% to 95% oF the pilot end 16.
In each of the sections shown in Figures 4 through 6, it can be seen that each of the arcuate surfaces 36, 38 is connected to a cutting surface 26 or 28 by a concave surface 44, 46 the concave surface forming the base of the flute 18 or 20 over the length of the pilot end 16.
Referring to Figures 7 and 8, a fastener 10 of the type described with reference to Figures 1 through 6 is shown having a hex head ~0 for driving the fastener. The fastener 10 is shown in ~L2~5~
its drilling position having progressed through the workpiece W
forming an opening H therein by rotation during the yet incomplete drilling operation. As will be noted, when the fastener 10 rotates to its position shown in Figure 7 there is a substantial space formed between the fastener and the opening H providing for material to be moved into the flutes 18 and 20 and subsequently removed from the opening during the operation. The drilling itself takes place by the action of the cutting edges 26, 28 and 30, 32 of the fastener 10 as shown positioned in Figllre 8.
Referring to Figure 9, there is a alternate embodiment of the invention similar to that shown in Figures 1 through 8. The Fastener 10a shown in Figure 9 is provided with threads 14a which extend down onto the pilot end 16a which is otherwise constructed in accordance with ~he description of Figures 1 through 8, above.
In Figure 10, there is shown a die which is constructed to form the fastener o~ Figures 1 through 9 by a Forging process. The die 48 is one of a pair of dies, or a die set, similarly constructed, which when forced together under high pressure are capable of forming the pilot end 16 of the fastener 10.
With the above described fastener, the objective of the invention have been achieved since the resultant shape of the point forging dies which are employed to form the elliptical cross section forces the excess headed blank material to flow more naturally and ~ 7 ~i~3~
easily from the point forging die contour, thereby reducing the resultant bursting stresses that accompany the compaction of material during the forging operation. Also, by forming the cutting surfaces 22 and 24 such that they meet the arcuate surfaces 36 and 38 of the lands at the concave surfaces 44 and 46, there are no sharp edges provided in the die structure to cause die failure. The elliptical reduction in cross sectional area also allows for a greater thickness of material in the forging dies at the point of greatest pressure, which strengthens the forging die and thus reduces breakaye. As also is evident from Figures 7 and 8 of the drawing, the new configuration achieves nearly 360 of clearance for chip and material renloval, that is, since the end points of the major axis of the elliptical cross section and the cutting edge of the point are the only points in contact with the material being drilled there is a reduced possibility of drilled material binding the drill point with the resultant slow down of drilling.
The fastener 10 has therefore provided an improvement over drilling and thread forming fasteners of the forged type which are known in the prior art and the configuration has proven to be advantageous in those applications where high carbon steels and stainless steel are employed in the manufacture of this type of fastener.
BACKGROUND OF THE INVENTION
The present invention relates to a rotary threaded fastener of the self-drilling and threading type, and more particularly to a fastener of that type which is manufactured by a pair of forging dies.
Various threaded fasteners of the self-drilling and thread forming type are known in the art, some of which are particularly adopted for manufacture by a milling process, while others are manufactured by a forging process which employs a pair of matched dies. A typical example of the type oF drilling and thread forming Fastener which is preferably formed by the forging process is shown in U.S. Patent No. 3395603, issued August 6, 1968 to E.J. Skierski and assigned to khe assi~nee of the present invention. Fasteners manufactured in accorclance with the teachings of this patent have met with wide acceptance as they provide a fastener which is simple to use, requiring no pre-drilling of the structure to which it is assembled, and fasteners of this type have proven to be easy to manufacture by mass production methods.
Recently, however, there has been a demand for self-drilling fasteners to be manufactured from high carbon steel, stainless steel, or metallic alloys which are of a hardness exceeding those of normal requirements. In some instances, it has been found that the ~2~8~
forging dies employed to manufacture a drill point on these fasteners is susceptible to premature breakage, when these harder materials are employed. It is considered that the stresses inherent in present point forging die configurations trap the harder material of the headed blank being worked on during the point forging operation, and that the entrapment of the blank material and its subsequent cold flow generates excessive stresses in the point forging die, causing in some instances, a premature point forging die breakage.
With the wide use of the self-drilllng and thread forming fasteners there has also been a requirement for the reduction in drilling time of the fastener. While existing point configurations which contain two flutes provide a satisfactory drill time in most applications, it is considered tilat they do not have sufficient clearance for chip flow to remove drilled material from the resultant hole, and thus to reduce drilling time. This occurs particularly when multi-layered assemblies of similar and dissimilar materials are operated upon . Such failure to remove drilled material can result in binding between the point and drilled hole surface causing excessive heat generation and resultant slower drill times.
The present invention therefore has as an object to provide a drilling and thread forming fastener of the type manufactured by a die forging process, which is effective to facilitate an increase in point forging die life.
Another object of the present invention is to provide a drilling and thread for~ling fastener wherein a greater clearance for escape of drilling chips is provided in the resultant drilled hole, during the dril1ing process.
Another object of the present invention is to provide a drilling and thread forming fastener which is susceptible to a reduction in drilling time over those drilling and thread fornning fasteners of the prior art.
~27~8~
SUMMARY OF THE INVENTION
The aforementioned objects and other objectives which will become apparent as the description proceeds are accomplished by providing a drilling and thread forming fastener having a threaded shank and a pilot end wherein the pilot end has a transverse major axis and a transverse minor axis intersecting at the center line of the fastener. A pair of flutes extending longitudinally over the pilot end serve to form a pair of cutting surfaces, in cross-section defining the major axis. A pair of lands concentric with the center line of the shank are each formecl of an arcuate surface extending outwardly to define the minor axis at its radial extent on any cross section of the pilot end. A substantially wedged shaped cuttiny tip is formed at the ternlinal portion of the pilot end. The minor axis increases in a linear progression from adjacent the cutting tip to a point remote from the cutting tip to thereby form an angular portion of said pilot end which longitudinal outer surface defines an angle with the fastener center line.
In a more detailed sense, the cutting surfaces are formed substantially parallel to one another over a greater portion of the pilot end angular portion.
h pair of mating dies are also provided for forming the above described structure in a forged pointing process, the inner surface ~;~75~
of the dies substantially conforming to the confi~uration set forth above.
~275~
BRIEF DESCRIPTION OF THE DRAWINGS
Reference is made to the accompanying drawing in which there is shown an illustrative embodiment of the invention from which its novel features and advantages will be apparent wherein FIG. 1 is a fragmentary elevational view showing a portion of a drilling and thread forming fastener constructed in accordance with the teachings of the subject invention;
FIG. 2 is an elevational view showing the fastener portion of FIG. 1 rotated through 90;
FIG. 3 is an encl view showing further details of the fastener of FTGS. 1 and 2;
FlG. 4 is a sectional view taken along the lines IV-IV of FIG.
3 showing details of the outer peripheral configuration of the fastener of FIGS. 1 though 3 at that section;
FIG. 5 is a sectional view taken along the lines V-V of FIG. 3 showing details of the outer peripheral configuration at that section;
FIG. 6 is a sectional view taken along the lines IV-IV of FIG.
3 shohing details of the outer peripheral configuration of the fastener of FIGS. 1 through 3 at that section, ~2~751 341) FIG. 7 is an elevational view similar to FIG. 2 showing the entire fastener of FIGS. 1 through 3 during the drilling operation;
FIG. 8 is a fragmentary elevational view similar to FIG. 1 showing the fastener of FIG. 7 rotated through 90 during the drilling operation;
FIG. 9 is a fragmentary elevational view showing an alternate embodiment of the structure of FIGS. 7 and 8; and FIG. 10 is a perspective view showing one of a pair of dies which comprise the d;e set for manufacture of the fastener shown in FIGS. 1 through 9.
~275~
DESCRIPTION OF A PREFERRED EMBODlMENT
Referring now to the drawings, and in particular to Figures I
through 3, there is shown a dril1ing and threaded forming fastener 10 having a shank 12 bearing the continuous thread 14 and a pilot end 16. The fastener 10 is substantially symmetrical about the center line oF the shank 12 and has a transverse major axis XX and a transverse minor axis YY intersecting at the center line. A pair of flutes 18 and 20 are formed in the pilot end 16 and extend longitudinally over the length of the pilot end to form a pa-,r of cutting surfaces 22, 24 extending along the major ax;s and in general defining the extent of the major axis of the fastener at any section thereof.
Each of the cutting surfaces 22 and 24 defines a cutting edge 26, 28 running substantially parallel to the center line of the fastener and terminating in an angular portion 30, 32. Each oF the angular portions 30 and 32 of the cutting edge terminates at a wedge shaped cutting tip 34. The cutting tip is disposed for preliminary entry into the metal surface to provide a lead for the cutting edges 30, 32, 26 and 28.
A pair of arcuate surfaces 36 and 38 extend along the length of the pilot end and terminate at an angular surface 40 and 42, ~L~7 5 ~34L~9 respectively, which extend toward the center line of the fastener to join the cutting tip 34.
Referring now to Figures 4 through 6 it will be noted that as the cross section of the pilot end 16 progresses from the cutting tip 34 to the threaded shank 12, the major axis remains substantially constant while the minor axis increases, approaching the length of the major axis but remaining less throughout the length of the pilot end.
The taper of the pilot end 16 is considered to extend from the minimum dinlension M as shown in Figures 2 and 3, to a maximum dimension W which is slightly less than the dimension of the X-X
axis at that point. The minimum dimension M is in the range of 20%
to 50, of the dimension W, and the taper generally extends over a length L which is in the range between 75% to 95% oF the pilot end 16.
In each of the sections shown in Figures 4 through 6, it can be seen that each of the arcuate surfaces 36, 38 is connected to a cutting surface 26 or 28 by a concave surface 44, 46 the concave surface forming the base of the flute 18 or 20 over the length of the pilot end 16.
Referring to Figures 7 and 8, a fastener 10 of the type described with reference to Figures 1 through 6 is shown having a hex head ~0 for driving the fastener. The fastener 10 is shown in ~L2~5~
its drilling position having progressed through the workpiece W
forming an opening H therein by rotation during the yet incomplete drilling operation. As will be noted, when the fastener 10 rotates to its position shown in Figure 7 there is a substantial space formed between the fastener and the opening H providing for material to be moved into the flutes 18 and 20 and subsequently removed from the opening during the operation. The drilling itself takes place by the action of the cutting edges 26, 28 and 30, 32 of the fastener 10 as shown positioned in Figllre 8.
Referring to Figure 9, there is a alternate embodiment of the invention similar to that shown in Figures 1 through 8. The Fastener 10a shown in Figure 9 is provided with threads 14a which extend down onto the pilot end 16a which is otherwise constructed in accordance with ~he description of Figures 1 through 8, above.
In Figure 10, there is shown a die which is constructed to form the fastener o~ Figures 1 through 9 by a Forging process. The die 48 is one of a pair of dies, or a die set, similarly constructed, which when forced together under high pressure are capable of forming the pilot end 16 of the fastener 10.
With the above described fastener, the objective of the invention have been achieved since the resultant shape of the point forging dies which are employed to form the elliptical cross section forces the excess headed blank material to flow more naturally and ~ 7 ~i~3~
easily from the point forging die contour, thereby reducing the resultant bursting stresses that accompany the compaction of material during the forging operation. Also, by forming the cutting surfaces 22 and 24 such that they meet the arcuate surfaces 36 and 38 of the lands at the concave surfaces 44 and 46, there are no sharp edges provided in the die structure to cause die failure. The elliptical reduction in cross sectional area also allows for a greater thickness of material in the forging dies at the point of greatest pressure, which strengthens the forging die and thus reduces breakaye. As also is evident from Figures 7 and 8 of the drawing, the new configuration achieves nearly 360 of clearance for chip and material renloval, that is, since the end points of the major axis of the elliptical cross section and the cutting edge of the point are the only points in contact with the material being drilled there is a reduced possibility of drilled material binding the drill point with the resultant slow down of drilling.
The fastener 10 has therefore provided an improvement over drilling and thread forming fasteners of the forged type which are known in the prior art and the configuration has proven to be advantageous in those applications where high carbon steels and stainless steel are employed in the manufacture of this type of fastener.
Claims (8)
1. A drilling and thread forming fastener comprising a threaded shank and a pilot end, said pilot end having a transverse major axis and a transverse minor axis intersecting at the center line of said fastener, a pair of flutes extending longitudinally over the extent of said pilot end to form a pair of cutting surfaces, in cross-section defining said major axis , a pair of lands concentric with the center line of said shank, each formed of an arcuate surface extending outwardly to define said minor axis at its radial extent on any cross-section of said pilot end and a substantially wedge shaped cutting tip formed at the terminal portion of said pilot end, wherein said minor axis increases in a linear progression from adjacent said cutting tip to a point remote from said cutting tip to thereby form an annular portion of said pilot end which longitudinal outer surface defines an angle with said fastener center line.
2. The fastener of claim 1 wherein said cutting surfaces are substantially parallel to one another over a greater portion of said pilot end angular portion.
3. The fastener of claim 1 wherein each said land is formed of a convex arcuate surface extending from the outer edge of one of said cutting surfaces to a similar diameter concave surface formed between said land and the inner edge of said other cutting surface and connecting the two.
4. The fastener of claim 1 wherein the minimum dimension of said minor axis is in the range of 20% to 50% of the maximum dimension of said minor axis.
5. The fastener of claim 1 wherein the length of said angular portion of said pilot end is in the range between 75% to 95% of said pilot end.
6. The fastener of claim 2 wherein said land is formed of a convex arcuate surface extending from the outer edge of one of said cutting surfaces to a smaller diameter concave surface formed between said land and the inner edge of said other cutting surface and connecting the two.
7. The fastener of claim 6 wherein the minimum dimension of said minor axis is in the range of 20% to 50% of the maximum dimension of said minor axis.
8. The fastener of claim 7 wherein the length of said angle of said pilot end is the range of 75% to 95% of said pilot end.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US76558185A | 1985-08-14 | 1985-08-14 | |
| US765,581 | 1985-08-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1275840C true CA1275840C (en) | 1990-11-06 |
Family
ID=25073921
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000515903A Expired - Fee Related CA1275840C (en) | 1985-08-14 | 1986-08-13 | Drill screw |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS6241416A (en) |
| AU (1) | AU582457B2 (en) |
| CA (1) | CA1275840C (en) |
| DE (1) | DE3626627C2 (en) |
| FR (1) | FR2586275B1 (en) |
| GB (1) | GB2178986B (en) |
| IT (1) | IT1197865B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2511769B2 (en) * | 1991-05-30 | 1996-07-03 | エヌ．ジアンヌズィ ルイス | Self drill anchor |
| US5129901A (en) * | 1991-06-10 | 1992-07-14 | Decoste Vern X | Cannulated orthopedic screw |
| US6382892B1 (en) * | 2001-01-16 | 2002-05-07 | Dave C. Hempfling | Wall anchor with improved drilling tip |
| JP2003222116A (en) * | 2002-01-31 | 2003-08-08 | Honda Motor Co Ltd | Self-tapping bolt |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DD81268A (en) * | ||||
| DD72426A (en) * | ||||
| DE1938944U (en) * | 1966-02-05 | 1966-05-18 | Lennewerk Altena G M B H Schra | TIN DRILLING SCREW. |
| US3395603A (en) * | 1966-09-13 | 1968-08-06 | Parker Kaion Corp | Rotary threaded fasteners |
| DD83671A1 (en) * | 1969-12-23 | 1971-08-05 | Dieter Dr-Ing Roehrich | Bohrtreibschraube |
| US4147088A (en) * | 1977-03-16 | 1979-04-03 | Nl Industries, Inc. | Drill screw |
| US4192217A (en) * | 1978-07-17 | 1980-03-11 | J. Schwartzman Manufacturing & Supply Co. | Self-drilling screw |
| US4233880A (en) * | 1978-07-20 | 1980-11-18 | Illinois Tool Works Inc. | Stainless steel drill screw |
| GB2100628B (en) * | 1981-06-25 | 1985-04-11 | Shinjo Seisakusho Yk | A drill screw |
| JPS597046A (en) * | 1982-07-03 | 1984-01-14 | 日東紡績株式会社 | Synthetic-resin laminated board enabling sharp cutting by laser beam |
| US4836730A (en) * | 1985-01-17 | 1989-06-06 | Emhart Industries, Inc. | Fastener |
-
1986
- 1986-08-06 DE DE3626627A patent/DE3626627C2/en not_active Expired - Fee Related
- 1986-08-11 GB GB8619508A patent/GB2178986B/en not_active Expired
- 1986-08-13 CA CA000515903A patent/CA1275840C/en not_active Expired - Fee Related
- 1986-08-13 FR FR868611681A patent/FR2586275B1/en not_active Expired - Fee Related
- 1986-08-13 AU AU61109/86A patent/AU582457B2/en not_active Ceased
- 1986-08-13 IT IT21477/86A patent/IT1197865B/en active
- 1986-08-14 JP JP61191182A patent/JPS6241416A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE3626627C2 (en) | 1995-03-16 |
| GB2178986B (en) | 1989-12-28 |
| IT1197865B (en) | 1988-12-21 |
| IT8621477A1 (en) | 1988-02-13 |
| GB2178986A (en) | 1987-02-25 |
| FR2586275A1 (en) | 1987-02-20 |
| IT8621477A0 (en) | 1986-08-13 |
| JPS6241416A (en) | 1987-02-23 |
| GB8619508D0 (en) | 1986-09-24 |
| AU582457B2 (en) | 1989-03-23 |
| FR2586275B1 (en) | 1990-01-05 |
| AU6110986A (en) | 1987-02-19 |
| DE3626627A1 (en) | 1987-02-19 |
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