CN1758977A

CN1758977A - Spade drill bit

Info

Publication number: CN1758977A
Application number: CN03826138.3A
Authority: CN
Inventors: 于尔根·维克; 格雷戈里·A·菲利普斯
Original assignee: Credo Technology Corp
Current assignee: Robert Bosch Tool Corp
Priority date: 2003-03-11
Filing date: 2003-03-11
Publication date: 2006-04-12
Anticipated expiration: 2023-03-11
Also published as: WO2004080632A1; EP1606073A1; AU2003225722A1; CN1758977B; EP1606073A4; EP1606073B1

Abstract

A spade drill bit comprises a shaft having one end configured to be engaged to a driving tool and a cutting head attached at an opposite end of said shaft. The cutting head includes a center point having threads defined thereon, including continuous threads adjacent the tip and discontinuous threads thereafter toward the base.

Description

Spade drill bit

Technical field

The present invention relates to a kind of drill bit.More specifically, the present invention relates to shovel the drill bit of shape type.

Background technology

A kind of traditional Spade drill bit is shown in Figure 1A-C.Bore 2 and have the cutting head 6 that is positioned at the slender axles end.The opposite end of axle 4 preferably is equipped with the hexagon plane 5 that is used to be engaged on traditional drill chuck inside.As best image among Figure 1B, head 6 is flat basically and be equipped with cutting edge 22 and 24.Center top 16 is along the longitudinal axis setting of boring 2.The excircle that bores is equipped with cutting straight-

tooth

26,28.

In use, top 16 of rotary drilling 2 at first thrust workpiece and serve as the centre pilot device that is used to bore.In the time of in boring further propelling workpiece, straight-tooth begins cutting material.At last, as the bit is advanced further, cutting

edge

22,24 begins to scrape the thin layer of turning work piece.Bore 2 and continue to thrust workpiece till it is in as shown in Figure 2 position, cut at this place straight-

tooth

26,28 and penetrate workpiece material.When the user of drill bit prepared to exit the hole, the straight-

tooth

26 and 28 that traditional shovel shape bores often pulled workpiece 30.

In case the outermost portion of straight-tooth leaves material 30, straight-tooth just makes the drill bit pulling self invade in the material backward.This is normally owing to the anterior angle 6 on the straight-tooth of shovel shape brill, and this angle is approximately 15 in typical boring ".When drill bit began to draw in the material by straight-tooth, the user will run into continually and be commonly called the wrench that pulls.Pull and can cause the explosion of wooden rear portion and split because not the last part of cutting material 31 be pushed out rather than be cut off.

Another problem relevant with the existing Spade drill bit of this class is that straight-

tooth

26,28 stands localized hyperthermia and high wear rate continually.In order to address these and other problems, studied the green bit 106 shown in Fig. 3 A-C.This brill 106 comprises the axle 104 that at one end has hex drive features 105 and stop at drill bit 106 places of opposite end.Drill bit 106 comprises center point 116 and two cutting edges 122,124.

Opposite with the existing brill shown in Figure 1A-C, the cutting edge 122,124 of the brill of Fig. 3 A-C is round, so the edge leaves workpiece material in the substantially the same time, as shown in Figure 4.The risk that this configuration has reduced the wood workpiece explosion and split, and reduced and bore 2 relevant wearing and tearing and temperature problems.

The head of the brill among Fig. 3 A-C can improve as shown in Figure 5.More particularly, head 106 ' center point 116 ' be threaded, like this, top 116 ' lateral margin just define a series of grooves 137.It is self-feeding that threaded top 116 ' permission is bored.In other words, when the rotation of the brill of Fig. 5, threaded top engagement workpiece and drawing the bit in the material.When this feature has reduced to thrust workpiece institute greatly the user the thrust that must apply.

Can to as shown in Figure 5 brill top 116 ' on screw thread the different pitch or the number of threads of per inch are provided.In typical configuration, screw thread changes in the scope of 16-26TPI.Fewer purpose screw thread makes brill more effectively thrust workpiece, and the screw thread more for number is then opposite.In a kind of improvement, threaded top 116 ' the degree of depth of the groove of arranging along top length 137 can be different.More particularly, screw thread top 116 ' the degree of depth at pedestal place can be greater than the place, tip.This feature makes threaded most advanced and sophisticated 116 ' more impacts that can resist the securing member of bump nail or other embedding workpiece inside.

Summary of the invention

In one embodiment of the invention, provide a kind of Spade drill bit, it comprises that having an end is designed to and the axle of driven tool engagement and the cutting head at the place, opposite end that is connected axle.Cutting head comprises center point and the common a pair of cutting edge that extends radially outward from the pedestal of center point with most advanced and sophisticated and pedestal.In a feature of the present invention, center point is threaded and comprises the continuous thread at contiguous most advanced and sophisticated place and thereafter towards the discontinuous screw thread of pedestal.

In certain embodiments, continuous screw thread comprises tapered root, and has therefore increased the depth of thread towards the tip of center point.Tapered root occurs in the side projection figure of drill bit.On the other hand, when observing in plane figure, screw thread has the depth of thread of substantial constant.More particularly, center point comprises the relative plane with discontinuous screw thread adjacency.These planes define the wherein constant plane figure of the depth of thread.

In a preferred embodiment, center point comprises the relative lateral margin that inserts between the relative plane.Discontinuous screw thread is limited on these relative lateral margins.Cutting head is preferably included in the straight-tooth of the outboard end place qualification of each cutting edge, and like this, drill bit comprises a pair of radially outwardly disposed straight-tooth.

In another embodiment, cutting head comprises the opposed side edges between relative plane and the insertion plane.The plane adjacency of plane that these are relative and center point.Cutting head can comprise the external screw thread that is limited in the opposed side edges.The screw thread of described center point and the external screw thread of cutting head preferably have substantially the same thread pitch.Yet in certain embodiments, the externally threaded depth of thread is less than the depth of thread of center point.

Continuous screw thread extends predetermined distance from the tip of center point.In certain embodiments, continuous screw thread extends about two revolutions from the tip.Discontinuous screw thread continues and stops above the pedestal of center point from continuous screw thread.In comprising the embodiment of outboard spurs, discontinuous screw thread stops at the line place of extending between straight-tooth.

An object of the present invention is to provide a kind of energy-conservation drill bit for this reason.Another object of the present invention provides a kind of drill bit design, and wherein smear metal more is easy to remove from the hole that gets out.Another object of the present invention provides a kind of drill bit design, and it has reduced the vibration of boring and can produce the higher hole of quality.

Another object of the present invention provides a kind ofly to be had lower rate of depreciation and the time avoids the drill bit of too high local temperature in boring.Another object of the present invention provides a kind of drill bit, and when leaving the hole, this drill bit can leave wood workpiece under the situation that does not pull workpiece.

Another object of the present invention provides a kind of thread tapping and self-running drill bit.By the explanation with accompanying drawing of writing below, these and other objects of the present invention will become more apparent.

Description of drawings

Accompanying drawing has shown various embodiment of the present invention and has been used for illustrating principle of the present invention together with explanation.In the accompanying drawings:

Figure 1A, 1B and 1C are respectively top view, side view and the edge projection figure of traditional Spade drill bit.

Fig. 2 has shown that traditional shovel shape of Figure 1A-C bores the view that leaves wooden workpiece.

Fig. 3 A, 3B and 3C are respectively top view, side view and the end-views of improved Spade drill bit design.

Fig. 4 has shown that improved shovel shape bores the view that leaves wooden workpiece among Fig. 3 A-C.

Fig. 5 is the view that bores through the shovel shape that has threaded center point after improving among Fig. 3 A-C.

Fig. 6 is the top view according to the Spade drill bit of one embodiment of the present of invention.

Fig. 7 is the threaded top enlarged drawing of the Spade drill bit in the zone 7 of Fig. 6.

Fig. 8 is the threaded top enlarged side view that shows among Fig. 7.

Fig. 9 is the perspective view according to the Spade drill bit of optional embodiment of the present invention.

Figure 10 be as shown in Figure 9, the view of the parallel substantially brill of side.

Figure 11 be as shown in Figure 9, the view of the brill assembled towards auger spindle of side.

Figure 12 be as shown in Figure 9, side is towards the view of the brill of auger spindle expansion.

The specific embodiment

In detail with reference to the current various preferred embodiments of the present invention, wherein the example of the preferred embodiments of the present invention shows in the accompanying drawings now.In different figures, some structure uses similar reference number to come mark.

Referring to Fig. 6, wherein shown one embodiment of the present of invention, the drill bit 202 that wherein shovels the shape formula is included in the axle 204 that drive end 205 stops.Cutting head 206 forms at the place, opposite end of axle.These parts of drill bit 202 respectively with Figure 1A-C and 3A-C in brill 2 and 102 like similar.In other words, drive end 204 can have the hexagon-shaped configuration that cooperates with drill chuck, and head 206 can have flat shovel shape profile.Head 206 comprises center point 216 and cutting edge 222,224, just as aforesaid two existing drill bits.In addition, the head 206 of the embodiment of the invention can comprise straight-

tooth

226 and 228, and is similar with the straight-

tooth

26 and 28 of brill shown in Figure 1A-C.

Cutting head 206 comprises the inclined surface 223 and 225 corresponding with

cutting edge

222 and 224, as shown in Figure 9.These surfaces tilt along the direction of drill bit rotation.Side 220 can comprise the anterior angle of the edge upper end of adjacent sloped surfaces 223,225.These parts of drill bit 202 in the embodiment of the invention with in that to be numbered in 5,433,561 the like parts that shows and describe similar, wherein the disclosure of this patent is hereby incorporated by.

Yet head 206 is inequality with the existing drill bit of Fig. 1-5.For example, in a feature of the present invention, center point 216 is threaded, shown in the detailed view that amplifies in Fig. 7 and 8.Especially, center point 216 comprises a series of screw threads 240 that extend along top 216 length (perhaps height) basically.In a preferred embodiment, screw thread 240 almost extends to its pedestal 217 from the tip of center point 216, and boring 202 at least herein is bigger drill bits (being about 7/16 and bigger).For littler brill (being about 3/8 and littler), screw thread preferably stops above the pedestal 217 of center point 216, and most preferably only extends about 3/16 below center point tip 218 ".For bigger or less brill, screw thread 240 preferably stopped before the external diameter that arrives head 206.In other words, the height place of screw thread above cutting edge 222,224 stops, and promptly stops at the height place that approximates the straight-tooth 226,228 above the edge greatly.

According to the aspect of this embodiment, center point 216 comprises the relative plane 230 (Fig. 6) that overlaps with the plane 218 of head 206.Screw thread 240 forms edge screw thread 242 along the tapered side of center point then, as shown in Figure 7.These screw threads proceed to the tip 218 of center point.In this top projection (promptly for the plane in the plane 218 and 230), screw thread 240 comprises root 244 and the tooth top 245 that defines depth of thread d.In this preferred embodiment, be constant with respect to this degree of depth of plane figure of drill bit 206.This constant depth d makes drill bit 206 have sharp initial sword, and this sword only needs minimum pressure for big eurypalynous wood.In specific embodiment, this depth of thread d is approximately 0.05 inch.

The side view of threaded center point 216 has presented another view.Especially because top 216 major part comprises relative plane 230, so top contiguous it tip 218 partly be taper.In other words, screw thread 240 comprises the tapered root 246 at the top tip of adjacent central 218, as shown in Figure 8.Root is tapered with angle A, and in a preferred embodiment, the angle of this angle A and the center point taper in its plane figure as shown in Figure 7 is basic identical.In specific embodiment, angle A is according to the size of drill bit 206 and the angle of fixed about 28-45 degree.For

The brill of inch, angle A are approximately 33 degree.

In this part of center point, preferably the tooth top 247 of screw thread 240 drops on identical tooth top diameter place at the tooth top 245 with screw thread 240 bottoms.Therefore, in the lateral plan of threaded center point 2l6, screw thread 240 demonstrates the degree of depth of increase towards the tip 218 of center point.Screw thread 240 begins at leading edge 248 places, and wherein leading edge impels threaded center point 216 at first to penetrate into workpiece.

The screw thread 240 of center point 216 combines the self-starting feature with advancing feature automatically.In other words, the leading edge 248 of using screw thread to expose, brill can thrust workpiece at an easy rate.Only apply minimum thrust by the user on boring, screw thread just continues to thrust and brill can be pulled to workpiece along center point 216.These features of screw thread 240 have reduced the wearing and tearing that center point stands.In addition, the Spade drill bit of acquisition provides a kind of steady boring action that has faster rate than traditional existing drill bit.Boring action stably and feed rate can produce higher-quality hole in workpiece, when particularly workpiece material is wood.

Can provide different pitch for screw thread 240 according to the application-specific of boring.Generally speaking, the brill that has than fine pitch can pierce workpiece quickly, though and bigger pitch can produce slower bore rate.In specific embodiment, screw thread 240 can have the pitch of 16TPI, and this is especially suitable for softer wood material.On the other hand, the pitch of 26TPI is more satisfactory for hard timber.The pitch of 20TPI is most wooden best for what use in building and the structure.This thread pitch is all effective in more soft harder wood, and wherein penetration rate descends when being used for hardwood, and this point is that everybody is in common knowledge.

In existing drill bit, for example in the open PCT application that is numbered WO98/05459 that its disclosure is hereby incorporated by in the disclosed drill bit, center point is only threaded on top side.This screw thread has been represented to the more improvement of the drill bit of morning, because it provides a kind of self-feeding characteristic to brill.By comprising continuous basically screw thread 247 at most advanced and sophisticated 218 places of center point 2l6, the present invention has made improvement on this feature.When boring when deeper promoting to enter workpiece, these screw threads thrust workpiece continuously, this make on existing drill bit the thrust that must keep reduce.In addition, as mentioned above, compare with the existing meter that is drilled with, the leading edge 248 of the exposure of screw thread 240 allows center point 216 to thrust workpiece at first.

It is the part of chip area 250 that the center point 216 of illustrated embodiment also is included in the form that limits on the relative plane 230 of center point.When central authorities top 216 pierced workpiece, these chip areas 250 improved the situation of removing of the smear metal of center point 216 generations.As best image goes out among Fig. 7, this chip area 250 be close to continuous thread 247 lower ends below beginning, and continue to enter the plane 218 of the head 206 that is close to cutting edge 222,224 belows.Top initial during with the workpiece engagement when central authorities, the shorter scope that continuous screw thread makes chip material pass through continuous thread 247 is upwards sent.Along with center point is further thrust workpiece, chip volume increases.If there is not chip area 250, the chip volume of increase tends to block the initial bore hole that forms of center point, thereby increases required thrust, has improved the heat accumulation in the bore hole and has reduced life-span of threaded core 216.Therefore, chip area 250 discharges the boring of chip material as quickly as possible, still keeps the useful feature of continuous thread 247 simultaneously.

In the embodiment of Fig. 6, drill bit 202 comprises smooth side 220.In optional embodiment of the present invention as shown in Figure 9, drill bit 202 ' the be included in screw thread 260 of relative side 220 ' middle qualification.As shown in Figure 9, drill bit 202 ' can comprise and as shown in Figure 6 brill 202 similar features.Yet, seen as Fig. 9, the side comprise a series of basically along the side 220 ' the groove 260 of gamut.These grooves 260 can form in the machined into that is used for cutting thread.Therefore, head 206 ' opposed side edges 220 ' on groove 260 constitute basically extend head 206 ' a plurality of sections of screw of length.

These external screw threads 260 occur at screw thread 240 stopping places of center point 216.In other words, in case straight-tooth 224,226 contact workpieces, head 206 ' screw thread 260 just with workpiece material engagement and impel and drill into workpiece.When cutting edge 222,224 beginning scraping workpiece materials, screw thread 260 continues to draw into workpiece.

When straight-tooth 226,228 arrives the end of workpiece bore, just realized the benefit that external screw thread 260 is provided.As illustrated during the PCT that is numbered WO98/05459 that discusses in the above announces, the problem that the straight-tooth on the Spade drill bit exists is that straight-tooth tends to pull in the cut end vicinity.Have been found that to bit head 206 ' side 220 ' augment screw thread 260 help to make drill bit to pass advancing of material held stationary, even when boring when breaking through the workpiece opposed side edges.

Preferred screw thread 260 is followed the thread pitch identical with the screw thread 240 of center point 216.On the other hand, preferred screw thread 260 has the degree of depth more shallow than the screw thread of center point.In a preferred embodiment, screw thread 260 has the only about half of degree of depth of the depth d of center point threads 240.In specific embodiment, screw thread 260 has the degree of depth that is approximately the 0.20-0.25 inch.The preferred this more shallow depth of thread because screw thread 260 want the inswept circumferential path bigger than the screw thread of tapered center point 216,

The scope of continuous thread can be used and difference according to specific drill bit.In most of preferred embodiments, for the drill bit of standard thickness (promptly be approximately 0.080 inch thick), continuous thread 240 approximately extends two revolutions.The scope of continuous thread 247 also can be decided according to the length (perhaps height) of center point.In typical shovel shape bored, center point 216 reached about 0.50 inch of cutting edge 222,224 tops of head 206.In this typical situation, continuous thread 247 approximately extends 0.10 inch from most advanced and sophisticated 218.

In a preferred embodiment, drill bit 202 ' side 220 ' substantially parallel, as shown in figure 10.Yet the side that can estimate to have screw thread 260 can be according to selectable towards arranging, shown in Figure 11 and 12.Especially, as shown in Figure 11, side 220 " can be assembled towards auger spindle 204 with angle M-.This convergence can begin at the straight-tooth place or begin at cutting edge 222,224 downstream parts.

Perhaps side 220 can be towards auger spindle 204 expansions, as shown in figure 12.Therefore, side 220 can expand with angle M+.(should be appreciated that screw thread 260 is also in side 220 " and on 220 ).Preferred convergence and expansion angle are all on the magnitude of about 1 degree.When drill bit deeper advanced in the workpiece, side 220 of expansion were so that drill bit is stable.On the other hand, the side 220 of convergence " can reduce to be used for rotary drilling-head and thrust the required power of workpiece.When the screw thread of the expansion that increases when diameter was widened bore hole gradually, threaded expansion side 220 also can produce smooth or " cleaning " bore hole that penetrates workpiece.Parallel side 220 ', " or the selection of side 220 of expansion can be decided according to the driving torque of the brill of the character of workpiece material and drill bit engagement for the side 220 assembled.For example, when brill is electric portable drill, wish driving force and drilling time are reduced to minimum, so the convergence of preferred Figure 11 is bored.On the other hand, when obtaining stronger brill, just wish to use the expansion drill bit of Figure 12.

Drill bit in the illustrated embodiment can for example form being numbered in the process of describing in 5,433,561 the United States Patent (USP) according to known procedures, and wherein this patent is incorporated herein by reference.External screw thread 260 on the side 220 of drill head 206 preferably is used to produce the lathe formation of screw.The screw thread 240 preferred tapered thread blanking dies that use on the center point form.Should be appreciated that tapered die can not cut out screw thread in the plane 230 of center point, because these surfaces are positioned at the tapered diameter below of center point.On the other hand, contiguous most advanced and sophisticated 218 partly keep its taper shape to dispose in the center point, because the tapered diameter of this part is less than the thickness of bit head 206.

Showing and choosing these embodiment is for principle of the present invention and application thereof are described best, thereby make others skilled in the art can use the present invention best in different embodiment and carry out various improvement, wherein these improvement are applicable to the special-purpose of expection.Scope of the present invention is intended to limit by the claim of enclosing.

For example, external screw thread 260 can use separately, combine with the screw thread 240 of center point or not use, and this requirement according to drill bit is decided.In less brill, preferably only use threaded center point, and on the side of bit head, do not have screw thread.Yet according to the present invention, constant in the embodiment of expection a bit is to provide continuous screw thread at 218 places, tip of center point, and this continuous screw thread partly locates to become gradually discontinuous screw thread on the plane of center point.

The embodiment that shows is best suited for the boring that penetrates wood material.The scope of wood material to harder material, and has been carried out suitable change at different sizes from softer material as mentioned above.Can expect that these brills can be applied to drill other material that has similarity with wood material.

Claims

1. Spade drill bit comprises:

Has the axle that is designed to an end of driven tool engagement;

At the cutting head that the place, an opposite end of described axle connects, described head comprises:

Center point with most advanced and sophisticated and pedestal;

Usually radially from the outward extending a pair of cutting edge of the described pedestal of described center point;

And the screw thread that limits on the described center point, described screw thread comprises the continuous thread at contiguous described tip and thereafter towards the discontinuous screw thread of described pedestal.

2. Spade drill bit as claimed in claim 1 is characterized in that described continuous screw thread comprises the root of taper.

3. Spade drill bit as claimed in claim 1 is characterized in that, described center point comprises the relative plane with described discontinuous screw thread adjacency.

4. Spade drill bit as claimed in claim 3 is characterized in that, described center point comprises the relative lateral margin that inserts between the described relative plane, and described discontinuous screw thread is limited on the described relative lateral margin.

5. Spade drill bit as claimed in claim 4 is characterized in that, described discontinuous screw thread has the constant depth of thread.

6. Spade drill bit as claimed in claim 5 is characterized in that, the described constant depth of thread extends to described continuous screw thread.

7. Spade drill bit as claimed in claim 1 is characterized in that, described cutting head is included in the straight-tooth of the outboard end qualification of each described cutting edge.

8. Spade drill bit as claimed in claim 1 is characterized in that, described cutting head comprises relative plane and inserts opposed side edges between the described plane.

9. Spade drill bit as claimed in claim 8 is characterized in that described cutting head comprises the external screw thread that is limited in the described opposed side edges.

10. Spade drill bit as claimed in claim 9 is characterized in that, the described screw thread of described center point and the external screw thread of described cutting head have substantially the same thread pitch.

11. Spade drill bit as claimed in claim 9 is characterized in that, the described externally threaded depth of thread is less than the depth of thread of described center point.

12. Spade drill bit as claimed in claim 9 is characterized in that, described opposed side edges is towards described dilatation shaft.

13. Spade drill bit as claimed in claim 9 is characterized in that, described opposed side edges is assembled towards described axle.

14. Spade drill bit as claimed in claim 1 is characterized in that, described continuous screw thread is from described most advanced and sophisticated about two revolutions of extending.

15. Spade drill bit as claimed in claim 1 is characterized in that, described discontinuous screw thread stops above the described pedestal of described center point.

16. Spade drill bit as claimed in claim 1 is characterized in that:

Described cutting head is included in the straight-tooth of the outboard end place qualification of each described cutting edge; And

The line place that described discontinuous screw thread extends between the straight-tooth of each described cutting edge stops.

17. Spade drill bit as claimed in claim 1 is characterized in that, described center point comprises at least one chip area that is limited to wherein.

18. Spade drill bit as claimed in claim 3 is characterized in that, described center point comprises at least one chip area that is limited in each described plane.

19. Spade drill bit as claimed in claim 19 is characterized in that, described chip area begins between the described pedestal of described continuous screw thread and described center point.