EP0153300A2 - Dispositif pour l'affûtage de forets hélicoidaux - Google Patents

Dispositif pour l'affûtage de forets hélicoidaux Download PDF

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Publication number
EP0153300A2
EP0153300A2 EP85890036A EP85890036A EP0153300A2 EP 0153300 A2 EP0153300 A2 EP 0153300A2 EP 85890036 A EP85890036 A EP 85890036A EP 85890036 A EP85890036 A EP 85890036A EP 0153300 A2 EP0153300 A2 EP 0153300A2
Authority
EP
European Patent Office
Prior art keywords
grinding
drill
grinding wheel
grinding surface
stop
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.)
Granted
Application number
EP85890036A
Other languages
German (de)
English (en)
Other versions
EP0153300A3 (en
EP0153300B1 (fr
Inventor
Raimund Wurscher
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Wurscher Raimund
Original Assignee
Wurscher Raimund
INTERMEDIUM AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Wurscher Raimund, INTERMEDIUM AG filed Critical Wurscher Raimund
Publication of EP0153300A2 publication Critical patent/EP0153300A2/fr
Publication of EP0153300A3 publication Critical patent/EP0153300A3/de
Application granted granted Critical
Publication of EP0153300B1 publication Critical patent/EP0153300B1/fr
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B3/00—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools
    • B24B3/24—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of drills
    • B24B3/26—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of drills of the point of twist drills

Definitions

  • the invention relates to a device for grinding twist drills with two relief surfaces and each relief surface of a helically rising flute, with a drive axis on which a grinding wheel with a grinding surface is axially movably mounted and spring-loaded against a drill guide piece arranged opposite the grinding surface, the drill guide piece having guide channels of different types Diameter for guiding a relief surface of drills of different diameters against the grinding surface, each guide channel has at least one guide pin which engages in a flute of the drill as well as a drill stop which acts on the relief surface which does not lie against the grinding surface and limits the advancement of the drill against the elastically receding grinding surface.
  • an adjustable stop acting between the drill guide piece and a component firmly connected to the grinding wheel is provided, which is intended to limit the spring travel of the grinding surface against the drill guide piece to an end position in which the grinding surface is closer to the guide pin than the drill stop.
  • the correct position of the relief surface of the drill in relation to the grinding surface is of decisive importance for the grinding result.
  • This position results from the radial position of the guide pins in the guide channel and, due to the helically increasing flutes of the drill, the distance of the guide pins from the drill stop. It is necessary to keep this distance small, because otherwise the differences in the rise of the flute helixes occurring in drills from different manufacturers would result in too large deviations from the correct position of the relief surfaces in relation to the grinding surface.
  • a disadvantage of these known devices is that the grinding surface becomes increasingly distant from the guide pins as the grinding wheel wears out, until finally the drills no longer reach the grinding surface.
  • the right distance between the Guide pins and the grinding surface must therefore be readjusted again and again with the help of the adjustable stop. Due to the small distance between the guide pin and the drill stop there is a risk that the grinding wheel will grind into the drill guide piece and damage the guide pin in the event of a setting error.
  • Another disadvantage of the known devices is that after long grinding of smaller diameter drills - i.e. of drills that do not touch the entire grinding surface when the grinding wheel rotates - wear of the grinding wheel results in a grooved or step-shaped deformation of the grinding surface. If a larger drill is then ground, this deformation is imprinted in the main cutting edge of this larger drill. If the deformation of the grinding wheel reaches a certain extent, the grinding wheel becomes completely unusable.
  • the invention is therefore based on the object of providing a drill grinding device of the type described in the introduction, in which the correct distance of the grinding surface from the guide pins and the original shape of the grinding surface are automatically maintained, and in which damage to the guide pins by the grinding wheel is prevented with certainty becomes.
  • a preferred embodiment of the grinding device according to the invention aims to ensure that the original shape of the grinding surface is restored not only after the drill has been withdrawn from the drill stop but also during grinding and thus continuously.
  • This embodiment is characterized in that several grinding wheel stops are arranged in the drill guide piece and distributed along the grinding surface and the grinding wheel is not only axially movable but also tiltable on the drive axis.
  • the drill with its relief grinding surface not pressed against the drill stop, presses the grinding wheel against the spring pressure away from the grinding wheel stops adjacent to the drill, while it is still pressed against the grinding wheel stops diametrically opposite the drill by the spring pressure.
  • the tiltability of the grinding wheel while maintaining high centering accuracy in a device with a grinding wheel carrier rigidly connected to the grinding wheel with a bore coaxial with the grinding wheel can be achieved in a simple manner in that the grinding wheel carrier has a low material thickness in the region of the drilling and the bore is penetrated by the drive axle with play.
  • at least one driver arm connected to the drive axle and at least approximately parallel to it can penetrate an opening in the grinding wheel carrier with play.
  • a sharpening of the grinding surface during grinding of a drill can therefore be achieved if, according to a further feature of the invention, the grinding surface and the abutment surfaces are expanded in the radial direction beyond what is necessary for grinding the largest drill that can be ground in the device, by choice the dimensions of these extensions, the pressure that arises between the extensions of the stop surfaces and the extension of the grinding surface is kept lower than the pressure that arises between the relief surfaces of the drill and the grinding surface.
  • carbide is generally used as the material for the grinding wheel stops.
  • the wear of hard metal is negligible when using the aluminum oxide disks customary for grinding drills of the type mentioned.
  • Other materials can also be used for the grinding wheel stops, for example polycrystalline diamond (multi-grain diamond) or cubic boron nitride (CBN).
  • polycrystalline diamond multi-grain diamond
  • CBN cubic boron nitride
  • materials that are harder than aluminum oxide (A1203) for the grinding grains of the grinding wheel for example silicon carbide (SiC).
  • FIG. 1 shows a longitudinal section in plane II 'in FIG. 2 through an embodiment of the grinding device according to the invention
  • FIG. 2 shows a view of the drill guide piece of the grinding device, seen in the direction of arrow A in FIG. 1, FIG. 3 a pair of guide pins on a larger scale
  • Fig. 4 the drill tip of a conventional twist drill
  • Fig. 5 is a plan view of the drill tip according to Fig. 4
  • Fig. 6 shows a longitudinal section through the drill guide piece and the grinding wheel in the region of a guide channel with a drill inserted up to the drill stop , on a larger scale
  • FIG. 7 shows a section as in FIG. 6, but in the area of a grinding wheel stop adjacent to the drill
  • FIG. 8 shows a section as in FIG. 6, but in the area of a grinding wheel stop opposite the drill.
  • 1 is a drive axle which has a pin 2 which can be clamped in the chuck of a drilling machine, not shown.
  • the grinding wheel 3 has the shape of a hollow cylinder.
  • Their internal conical actual grinding surface 4a can be described as the cutting surface of a cone with the hollow cylinder, which is coaxial with the hollow cylinder.
  • the width of the actual grinding surface 4a is selected so that it just covers the relief surface 5 of the largest drill that can be ground in the device.
  • the actual grinding surface 4a is widened outwards by a surface 4b perpendicular to the axis of the hollow cylinder.
  • the grinding wheel 3 is glued to a grinding wheel carrier 6.
  • the grinding wheel carrier 6 has a through-bore 7 which is coaxial with the grinding surface 4a, 4b and which is due to the low material Strength of the grinding wheel carrier 6 has a small axial extent.
  • This through hole 7 is penetrated by the drive shaft 1 with play, in that its diameter is somewhat larger than the diameter of the drive shaft 1.
  • the grinding wheel 3 is thus not only axially movable but also tiltable on the drive shaft 1.
  • a driver 8, 11 consists of a cup-shaped part 8, which is pushed onto the drive axle 1 with a central bore and is clamped between a locking ring 9 and a nut 10, and two driver arms 11, which project upwards from the rim of the pot and parallel to the drive axle 1 extend through the openings 12 in the grinding wheel carrier 6 with play.
  • the drive axle 1 is mounted by means of a ball bearing 13 in a drill guide piece which consists of parts 14 to 18 which are rigidly connected to one another.
  • guide channel body 14 of which is a guide channel body, through which guide channels 19 (FIG. 6) of different diameters extend parallel to the drive axis 1 for the longitudinal guidance of drills of different diameters to the grinding surface 4a.
  • the axes of the guide channels 19 lie in a cylinder jacket coaxial with the drive axis 1, the diameter of which is approximately equal to the inner diameter of the grinding wheel 3.
  • a hollow cylinder 14a on the guide channel body 14 surrounds the grinding wheel 3.
  • a handle 14c is formed on the guide channel body.
  • a guide pin carrier 15, 16 and a drill stop 18 are pressed onto the hollow cylinder 14b on the guide channel body 14.
  • the guide pin carrier consists of two rigidly interconnected plates 15 and 16.
  • the plate 15 has through holes 20 aligned with the guide channels 19, the diameter of which is equal to the diameter of the corresponding guide channel.
  • the plate 16 has openings 21 aligned with the through-holes 20, into which two guide pins 23 (FIG. 3) which are intended to engage in the flutes 22 of a drill protrude.
  • Each guide pin 23 has two stop edges 24 which limit rotation of a drill inserted into the corresponding guide channel 19 and between the guide pins 23 to the right and left.
  • One from the pilot pin Carrier 15, 16 protruding outward projection 25 extends into a corresponding recess 26 in the guide channel body 14 for exact alignment of the guide pin carrier 15, 16 with the guide channel body 14 (FIG. 2).
  • the drill stop 18 has the shape of a truncated cone with an outer conical stop surface.
  • grinding wheel stops 17 which are uniformly distributed along the grinding surface 4a, 4b and made of a material that is harder than the grinding wheel 3, in particular made of hard metal, are soldered to the guide pin carrier 15, 16. They each have a stop surface 17a and 17b which is parallel to the actual grinding surface 4a and the expanded grinding surface 4b and which are closer to the guide pins 23 than the stop surface of the drill stop 18.
  • a compression spring 27 is supported on the one hand against the sole of the driver 8 and on the other hand against the grinding wheel carrier 6 and presses the grinding surface 4a, 4b of the grinding wheel 3 against the stop surfaces 17a and 17b of the grinding wheel stops 17.
  • the grinding surface 4a, 4b lies Guide pin 23 closer than the stop surface of the drill stop 18th
  • the described grinding process gives the drill a central grinding within practically usable limits and both a sufficiently large relief grinding 28 as well as a suitable relief grinding angle (FIG. 4) and a suitable cross cutting angle (FIG. 5). If a larger relief 28 is required, the drill is ground in the next closest guide channel.
  • the drill with its relief surface 5 not pressed against the drill stop 18, presses the grinding wheel 3 away from the two grinding wheel stops 17 (FIG. 7) adjacent to the drill against the force of the spring 27, while the grinding wheel continues to press against the spring 27 is pressed against the two grinding wheel stops 17 (FIG. 8) lying more or less diametrically opposite one another and is worn by them.
  • the dulling effect of the grinding wheel stops 17 on the grains of the actual grinding surface 4a is prevented by choosing the width of the extended grinding surface 4b and the area dimension of the extended stop surfaces 17b of the grinding wheel stops 17 such that the resultant between the extended grinding surface 4b and the extended stop surfaces 17b Pressure is slightly less than the pressure that arises between the largest drill that can be ground in the device and the actual grinding surface 4a. As explained in more detail elsewhere, this results in a sharpening of the area of the grinding surface 4a touched by the drill during the grinding of a drill. The resulting deformation 29 of the grinding surface 4a, which is exaggerated in FIGS. 6 to 8, is hardly noticeable if the width of the expanded grinding surface 4b and the area dimension of the expanded abutment surfaces 17b are selected correctly.
  • the invention has been described above with reference to a preferred exemplary embodiment, but is in no way restricted to this.
  • the described embodiment is designed as an additional device for hand drills.
  • An exemplary embodiment according to the invention could also be designed as an autonomous unit with a built-in motor.
  • a satisfactory effect of the specific features of the invention taking into account both the grinding action of the wheel on the drill and the action of the grinding wheel stops on the grinding surface, should be achieved at a working speed of the grinding surface of about 3 to 30 m / s, the optimal effect is around 20 m / s.
  • the optimal effect is around 20 m / s.
  • an outer diameter of the grinding wheel of approximately 80 mm, this corresponds to approximately 700 rpm to 7000 rpm or 5000 rpm.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
  • Polishing Bodies And Polishing Tools (AREA)
  • Earth Drilling (AREA)
EP85890036A 1984-02-14 1985-02-13 Dispositif pour l'affûtage de forets hélicoidaux Expired EP0153300B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT0046384A AT380418B (de) 1984-02-14 1984-02-14 Einrichtung zum schleifen von spiralbohrern
AT463/84 1984-02-14

Publications (3)

Publication Number Publication Date
EP0153300A2 true EP0153300A2 (fr) 1985-08-28
EP0153300A3 EP0153300A3 (en) 1986-12-30
EP0153300B1 EP0153300B1 (fr) 1988-11-30

Family

ID=3491289

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85890036A Expired EP0153300B1 (fr) 1984-02-14 1985-02-13 Dispositif pour l'affûtage de forets hélicoidaux

Country Status (7)

Country Link
US (1) US4574528A (fr)
EP (1) EP0153300B1 (fr)
JP (1) JPS60180756A (fr)
AT (2) AT380418B (fr)
CA (1) CA1236697A (fr)
DE (1) DE3566510D1 (fr)
ES (1) ES540322A0 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT385703B (de) * 1986-07-07 1988-05-10 Wurscher Raimund Einrichtung zum schleifen von spiralbohrern
DE4038524A1 (de) * 1990-12-03 1992-06-04 Folke Werner Bohrerschleifeinrichtung
US9199315B2 (en) 2000-06-02 2015-12-01 Kennametal Inc. Twist drill and method for producing a twist drill which method includes forming a flute of a twist drill
CN114633155A (zh) * 2022-02-23 2022-06-17 河南中烟工业有限责任公司 一种麻花钻头的磨削靠模及磨削装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2800755A (en) * 1955-03-14 1957-07-30 Joseph D Perra Drill sharpener
DE2042014A1 (de) * 1969-10-07 1971-04-22 Wurscher Raimund Dr Phil Einrichtung zum Schleifen von Bohrern
DE1959470A1 (de) * 1969-11-27 1971-07-22 Wurscher Raimund August Einrichtung zum Schleifen von Bohrern
FR2242853A5 (en) * 1973-08-28 1975-03-28 Bosch Gmbh Robert Drill grinder with guide body - fixed guide pins engaging drill flutes screw adjusted towards grinding wheel

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE325210B (fr) * 1967-05-03 1970-06-22 R Wurscher
US3742652A (en) * 1970-03-06 1973-07-03 Black & Decker Mfg Co Drill sharpener
US4016680A (en) * 1974-04-01 1977-04-12 The Black And Decker Manufacturing Company Sharpener for twist drills including grinding wheel dressing means

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2800755A (en) * 1955-03-14 1957-07-30 Joseph D Perra Drill sharpener
DE2042014A1 (de) * 1969-10-07 1971-04-22 Wurscher Raimund Dr Phil Einrichtung zum Schleifen von Bohrern
DE1959470A1 (de) * 1969-11-27 1971-07-22 Wurscher Raimund August Einrichtung zum Schleifen von Bohrern
FR2242853A5 (en) * 1973-08-28 1975-03-28 Bosch Gmbh Robert Drill grinder with guide body - fixed guide pins engaging drill flutes screw adjusted towards grinding wheel

Also Published As

Publication number Publication date
ATE38952T1 (de) 1988-12-15
EP0153300A3 (en) 1986-12-30
US4574528A (en) 1986-03-11
JPS60180756A (ja) 1985-09-14
JPS6339377B2 (fr) 1988-08-04
ATA46384A (de) 1985-10-15
CA1236697A (fr) 1988-05-17
EP0153300B1 (fr) 1988-11-30
ES8602467A1 (es) 1985-12-01
AT380418B (de) 1986-05-26
ES540322A0 (es) 1985-12-01
DE3566510D1 (en) 1989-01-05

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