EP0003103A2 - Down-the-hole drill - Google Patents
Down-the-hole drill Download PDFInfo
- Publication number
- EP0003103A2 EP0003103A2 EP79100010A EP79100010A EP0003103A2 EP 0003103 A2 EP0003103 A2 EP 0003103A2 EP 79100010 A EP79100010 A EP 79100010A EP 79100010 A EP79100010 A EP 79100010A EP 0003103 A2 EP0003103 A2 EP 0003103A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- bit
- face
- drill
- flushing fluid
- hole
- 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
Links
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B10/00—Drill bits
- E21B10/36—Percussion drill bits
- E21B10/38—Percussion drill bits characterised by conduits or nozzles for drilling fluids
Definitions
- THIS INVENTION relates to down-the-hole drilling and provides improvements in the provision of flushing fluid in the vicinity of the bit head of a down-the-hole drill in order to facilitate the removal of rock chips from the hole.
- the fluid will normally be air but could be an air-liquid mixture or, in a purely hydraulic drill, liquid only.
- the hammer mechanism acts directly on a drill bit at the bottom of the hole and the forces on the bit are direct and large. It is therefore necessary to use a bit of considerable strength. Flushing fluid is supplied to the bit, often through a generally axial hole which extends through the shank of the bit to the face which acts on the floor of the hole, and sometimes through a series of grooves extending generally longitudinally along the shank of the bit and terminating at the face.
- a central bore in the bit is provided, terminating in an orifice at the centre of the face.
- An object of the invention is to provide in down-the-hole drilling means for improving the control of the flushing action of the flushing fluid and thereby making drilling more efficient than in known equipment and reducing wear of the bit.
- the invention provides a bit for a down-the-hole drill, the bit having a shank and a head and being formed with at least two cavities for conveying flushing fluid from the interior of the drill to the exterior, the first of the cavities extending to the face of the head, characterised in that the second cavity terminates above the face and is adapted to deflect upwards the flushing fluid which it conveys.
- the second cavity is conveniently a groove in the material of the bit, terminating in a zone above the level of the head and extending generally transversely with respect to the axis of the bit.
- the first and second cavities also preferably extend independently of each other in the bit, and preferably not more than one of them is a bore. There may be a plurality of the first and second cavities.
- the invention is particularly but not exclusively suitable for button bits, where the existence of the buttons allows a freer flow of fluid at the bit face than occurs in blade-type bits.
- the flow of flushing fluid to the face of the bit is preferably lesser than the flow of fluid deflected u p the hole.
- a pneumatic down-the-hole drill includes a casing 10 haying a lower end into which is fitted a bit 12 of the invention, seen only fragmentarily.
- the bit 12 has a shank 14 and a head 16.
- the upper part of the shank is conventional as regards the manner in which it is supported in the casing 10.
- the face 18 of the bit is adapted to carry a series of buttons fixed in blind holes 20, the buttons being removed for the sake of simplicity.
- the arrangements for imparting percussive force to the bit and for rotating the drill assembly in the hole are conventional.
- the shank 14 has an internal bore 22 which extends axially from the upper tip of the bit and merges near the head 16 with an oblique bore 24 having a mouth 26 in the face 18.
- the casing 10 of the drill includes an internal longitudinal groove 28 which extends along the full length of the shank 14 and which carries flushing air. It terminates at the end of the casing 10, where the flushing air is directed into a groove or channel 30 formed in the material of the bit 12 in the surface abutting the lower edge of the casing 10 and so shaped as to deflect the air arriving from the groove 28 outwards into the hole and upwards in it, thus back up the hole.
- the groove 30 shown, which leaves the drill at right angles to its vertical axis, is suitable for this purpose.
- the passages 22, 24, 28 and 30 are so sized in relation to the air supply in the drill that somewhat less than half the air flow, and preferably about 25%, arrives at the face of the bit through the bores 22, 24, the remainder being directed through the passage 28 and deflected by the groove 30 up the hole.
- the result is that a low pressure area is created in the hole at the level of the groove 30, and air and rock chips from below are drawn upwards into this zone and from it blown out of the hole.
- the effect is to reduce turbulence and to allow a steadier and more controlled flow of air across the force of the bit. The removal of chips is thus more effective in the face area.
- a drill casing 110 is fitted with a bit 112 that includes a shank 114 and a head 116.
- the head 116 has a face 118 with buttons (not shown) fixed in holes 120.
- the drill casing 110 has on one side an internal groove 122 which at its lower end joins a bore 124 formed obliquely in the material of the head of the bit and ends in a mouth 126 in the face 118.
- a longitudinal groove 128 on its side surface registers with the groove 122 in the wall of the casing 110 of the drill to form a passage of approximately the same cross-sectional area as the bore 124.
- the shank 114 of the bit 112 is provided, at 90° angular displacement round the axis of the shank from the bore 124, with a further groove 130 which extends the full length of the shank and joins a deflection groove 132 formed in the head of the bit.
- the groove 130 registers with a suitably shaped groove (not illustrated) in the inner surface of the casing 110 so that a further passage down the shank is created for air which passes out of the drill assembly through the deflection groove 132 and passes up the hole, creating a low pressure area below it to attract upwards air and rock chips.
- the air supply to the face'of the bit is delivered not through a bore but through a groove in the external surface of the bit, the groove following the general outline of the bit and terminating in an off-centre zone in the face.
- the second cavity may in this case be a bore in the bit but is preferably a further groove in the shank, conveniently one which registers with another groove formed in the casing, and terminating in a transverse extension such as the grooves 30 or 132 illustrated.
- the chief advantage of the invention is that it improves the control which can be exerted of the flushing action at the face by reducing or eliminating turbulence and closed air circuits, the venturi effect explained above being a secondary advantage.
Abstract
Description
- THIS INVENTION relates to down-the-hole drilling and provides improvements in the provision of flushing fluid in the vicinity of the bit head of a down-the-hole drill in order to facilitate the removal of rock chips from the hole. The fluid will normally be air but could be an air-liquid mixture or, in a purely hydraulic drill, liquid only.
- In a down-the-hole drill, the hammer mechanism acts directly on a drill bit at the bottom of the hole and the forces on the bit are direct and large. It is therefore necessary to use a bit of considerable strength. Flushing fluid is supplied to the bit, often through a generally axial hole which extends through the shank of the bit to the face which acts on the floor of the hole, and sometimes through a series of grooves extending generally longitudinally along the shank of the bit and terminating at the face.
- It is also known (from west German patent 1 238 864) to provide a pair of flushing holes in the bit, the holes leading from passages in the drill body to the top of the head and passing through the head. The holes are located opposite each other. It is however undesirable for the bit of a down-the-hole drill to be weakened by numerous internal cavities, so that a bit formed with two or more generally longitudinal holes through it is not as strong as may be wished. Two holes are however generally considered desirable where the bit is of the blade type, being provided because of the symmetry of the cruciform blade arrangement at the face of the bit. Apart from being structurally relatively weak, this arrangement also leads to undesirable turbulence and to closed air circuits at the bit head, which in turn lead to premature wear of the bit.
- In another arrangement (known from United States patent 3 225 841) a central bore in the bit is provided, terminating in an orifice at the centre of the face. There is also a series of downwardly sloping passages extending from the central bore to the sides of the bit, where the passages end in grooves which direct the flushing air downwards to sweep the face of the bit. This arrangement suffers from the structural weakness inherent in bits with several internal cavities, and there is again considerable turbulence at the face, where the streams of flushing fluid converge, and hence premature wear.
- In out-of-the-hole drilling technology it is common to provide a longitudinal channel for flushing fluid along the drill stem or string which extends from the drill body to the bit. In such drills the head of the bit is usually considerably larger in diameter, compared to the diameter of the stem behind it, than is the case in down-the-hole drills, where the reduction in cross-sectional area of the apparatus directly behind the head of the bit is'relatively slight since the casing housing the hammer mechanism is located immediately above the bit.
- In out-of-the-hole drilling, the reduction in cross-section mentioned above has the consequence that the flushing fluid tends to diffuse into the space in the hole immediately behind the head, slowing down the overall flow. This has an unfavourable effect on the flushing action since the velocity of the flushing fluid should be maintained if the fluid is to perform a proper sweeping action.
- To overcome this problem of out-of-the-hole drilling, it is known (for example from United Kingdom patent 1,071,418) to provide a central longitudinal bore through the drill bit, extending to the centre of the face, and also a series of further bores which extend from the central longitudinal cavity through the side wall of the bit, some being sloped towards the face and others away from the face. This arrangement divides the stream of flushing fluid and creates a venturi effect in which there is a high-pressure region at the face itself. Chips from the face are drawn from this area into a low-pressure region further up the hole where they are entrained in the rapidly moving stream of flushing fluid and conveyed up the hole.
- In such drills the bit is naturally weakened by the presence of multiple bores and such bits would be inapplicable in down-the-hole drilling. Moreover the characteristics of the fluid available for flushing are entirely different compared with down-the-hole drills. The less marked difference in relative areas between the head and the zone behind the head also reduces the theoretical desirability of the venturi effect.
- An object of the invention is to provide in down-the-hole drilling means for improving the control of the flushing action of the flushing fluid and thereby making drilling more efficient than in known equipment and reducing wear of the bit.
- The invention provides a bit for a down-the-hole drill, the bit having a shank and a head and being formed with at least two cavities for conveying flushing fluid from the interior of the drill to the exterior, the first of the cavities extending to the face of the head, characterised in that the second cavity terminates above the face and is adapted to deflect upwards the flushing fluid which it conveys.
- The second cavity is conveniently a groove in the material of the bit, terminating in a zone above the level of the head and extending generally transversely with respect to the axis of the bit. The first and second cavities also preferably extend independently of each other in the bit, and preferably not more than one of them is a bore. There may be a plurality of the first and second cavities.
- The invention is particularly but not exclusively suitable for button bits, where the existence of the buttons allows a freer flow of fluid at the bit face than occurs in blade-type bits.
- The flow of flushing fluid to the face of the bit is preferably lesser than the flow of fluid deflected up the hole.
- Ir. the drawings:
- Figure 1 is a simplified fragmentary longitudinal section through the lower end of a down-the-hole drill fitted with a bit of the invention;
- Figure 2 is an underplan view of the bit of Figure 1;
- Figure 3 is a view similar to Figure 1 of a further embodiment of the invention;
- Figure 4 is a view of the bit of Figure 3, similar to the view of Figure 2; and
- Figure 5 is a semi-section of the bit of Figures 4 and 5 showing a longitudinal flushing groove in it.
- In Figure 1, a pneumatic down-the-hole drill includes a
casing 10 haying a lower end into which is fitted abit 12 of the invention, seen only fragmentarily. Thebit 12 has ashank 14 and ahead 16. The upper part of the shank is conventional as regards the manner in which it is supported in thecasing 10. Theface 18 of the bit is adapted to carry a series of buttons fixed inblind holes 20, the buttons being removed for the sake of simplicity. The arrangements for imparting percussive force to the bit and for rotating the drill assembly in the hole are conventional. - The
shank 14 has aninternal bore 22 which extends axially from the upper tip of the bit and merges near thehead 16 with anoblique bore 24 having amouth 26 in theface 18. - The
casing 10 of the drill includes an internallongitudinal groove 28 which extends along the full length of theshank 14 and which carries flushing air. It terminates at the end of thecasing 10, where the flushing air is directed into a groove orchannel 30 formed in the material of thebit 12 in the surface abutting the lower edge of thecasing 10 and so shaped as to deflect the air arriving from thegroove 28 outwards into the hole and upwards in it, thus back up the hole. Thegroove 30 shown, which leaves the drill at right angles to its vertical axis, is suitable for this purpose. Thepassages bores passage 28 and deflected by thegroove 30 up the hole. The result is that a low pressure area is created in the hole at the level of thegroove 30, and air and rock chips from below are drawn upwards into this zone and from it blown out of the hole. The effect is to reduce turbulence and to allow a steadier and more controlled flow of air across the force of the bit. The removal of chips is thus more effective in the face area. - In the version of Figures 3 - 5, a
drill casing 110 is fitted with abit 112 that includes ashank 114 and ahead 116. Thehead 116 has aface 118 with buttons (not shown) fixed inholes 120. - The
drill casing 110 has on one side aninternal groove 122 which at its lower end joins abore 124 formed obliquely in the material of the head of the bit and ends in amouth 126 in theface 118. There is no axial bore in the shank of the bit, but alongitudinal groove 128 on its side surface registers with thegroove 122 in the wall of thecasing 110 of the drill to form a passage of approximately the same cross-sectional area as thebore 124. Thus flushing air in the interior of the drill is conveyed through the passage defined by thegrooves bore 124 and finally emerges in the drill hole through themouth 126, where it has a flushing action. - As is best seen in Figures 4 and 5, the
shank 114 of thebit 112 is provided, at 90° angular displacement round the axis of the shank from thebore 124, with afurther groove 130 which extends the full length of the shank and joins adeflection groove 132 formed in the head of the bit. Thegroove 130 registers with a suitably shaped groove (not illustrated) in the inner surface of thecasing 110 so that a further passage down the shank is created for air which passes out of the drill assembly through thedeflection groove 132 and passes up the hole, creating a low pressure area below it to attract upwards air and rock chips. - The combined action of the air stream directed into the floor of the hole and that deflected upwards from the floor of the
groove 132 is much as was described in relation to the embodiment of Figures 1 and 2. - Hote that in both the embodiments mentioned above the flushing cavity extending to the face of the bit is completely independent of the cavity supplying flushing air to the exterior of the bit above the face. This arrangement naturally calls for the air supply in the mechanism of the drill body above the bit to be divided into two streams.
- Among further variants (not illustrated) of the invention is one in which the air supply to the face'of the bit is delivered not through a bore but through a groove in the external surface of the bit, the groove following the general outline of the bit and terminating in an off-centre zone in the face. The second cavity may in this case be a bore in the bit but is preferably a further groove in the shank, conveniently one which registers with another groove formed in the casing, and terminating in a transverse extension such as the
grooves - In another variant there is not one but a plurality of cavities supplying flushing fluid from the interior of the drill to points on the periphery of the bit above the face for deflection up the hole to create a low-pressure zone drawing chips from below.
- In preliminary trials of drills of the invention under practical operating conditions it has been found that erosion and wear of the bit have been substantially reduced, in some cases increasing the life of the bit by more than 20% compared to comparable known bits.
- It would seem that the chief advantage of the invention is that it improves the control which can be exerted of the flushing action at the face by reducing or eliminating turbulence and closed air circuits, the venturi effect explained above being a secondary advantage.
Claims (11)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ZA780091 | 1978-01-06 | ||
ZA00780091A ZA7891B (en) | 1978-01-06 | 1978-01-06 | Down-the-hole drilling |
Publications (4)
Publication Number | Publication Date |
---|---|
EP0003103A2 true EP0003103A2 (en) | 1979-07-25 |
EP0003103A3 EP0003103A3 (en) | 1979-08-08 |
EP0003103B1 EP0003103B1 (en) | 1982-12-22 |
EP0003103B2 EP0003103B2 (en) | 1986-12-10 |
Family
ID=25572468
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP79100010A Expired EP0003103B2 (en) | 1978-01-06 | 1979-01-02 | Down-the-hole drill |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0003103B2 (en) |
AU (1) | AU522330B2 (en) |
FI (1) | FI69183C (en) |
NO (1) | NO151016C (en) |
ZA (1) | ZA7891B (en) |
Citations (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US321023A (en) * | 1885-06-30 | hammer | ||
US1943880A (en) * | 1930-05-08 | 1934-01-16 | Detachable Bit Corp Of America | Drill |
US2507221A (en) * | 1946-08-19 | 1950-05-09 | Phipps Orville | Single edge percussion bit |
US3155180A (en) * | 1962-04-27 | 1964-11-03 | Ingersoll Rand Canada | Drill bit with fluid passages |
US3225841A (en) * | 1962-08-31 | 1965-12-28 | Joy Mfg Co | Drilling apparatus |
US3269471A (en) * | 1963-11-26 | 1966-08-30 | Robert T Alexander | Rock drilling bit |
US3299974A (en) * | 1963-10-01 | 1967-01-24 | P & V Mining & Engineering Ltd | Percussive drill bits |
DE1238864B (en) * | 1966-03-17 | 1967-04-20 | Fritz Zimmermann | Countersunk hammer for large hole drilling machines |
GB1071418A (en) * | 1963-08-19 | 1967-06-07 | P & V Mining & Engineering Ltd | Improvements in rock-drilling tools |
CA871004A (en) * | 1966-06-24 | 1971-05-18 | A. Bendo Allen | Flushing bit |
FR2200434A1 (en) * | 1972-09-27 | 1974-04-19 | Boehler & Co Ag Geb | Pneumatic percussion drill hammer - with grooves as air vent channels on same side of hammer |
AU450556B2 (en) * | 1973-01-09 | 1974-07-11 | "improvements in rock drill bits" | |
US3866746A (en) * | 1973-08-27 | 1975-02-18 | Bakerdrill Inc | Rotary bore hole air hammer drive mechanism |
US3991834A (en) * | 1975-07-07 | 1976-11-16 | Curington Alfred R | Sampling airhammer apparatus |
-
1978
- 1978-01-06 ZA ZA00780091A patent/ZA7891B/en unknown
-
1979
- 1979-01-02 NO NO79790011A patent/NO151016C/en unknown
- 1979-01-02 EP EP79100010A patent/EP0003103B2/en not_active Expired
- 1979-01-04 FI FI790023A patent/FI69183C/en not_active IP Right Cessation
- 1979-01-05 AU AU43147/79A patent/AU522330B2/en not_active Ceased
Patent Citations (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US321023A (en) * | 1885-06-30 | hammer | ||
US1943880A (en) * | 1930-05-08 | 1934-01-16 | Detachable Bit Corp Of America | Drill |
US2507221A (en) * | 1946-08-19 | 1950-05-09 | Phipps Orville | Single edge percussion bit |
US3155180A (en) * | 1962-04-27 | 1964-11-03 | Ingersoll Rand Canada | Drill bit with fluid passages |
US3225841A (en) * | 1962-08-31 | 1965-12-28 | Joy Mfg Co | Drilling apparatus |
GB1071418A (en) * | 1963-08-19 | 1967-06-07 | P & V Mining & Engineering Ltd | Improvements in rock-drilling tools |
US3299974A (en) * | 1963-10-01 | 1967-01-24 | P & V Mining & Engineering Ltd | Percussive drill bits |
US3269471A (en) * | 1963-11-26 | 1966-08-30 | Robert T Alexander | Rock drilling bit |
DE1238864B (en) * | 1966-03-17 | 1967-04-20 | Fritz Zimmermann | Countersunk hammer for large hole drilling machines |
CA871004A (en) * | 1966-06-24 | 1971-05-18 | A. Bendo Allen | Flushing bit |
FR2200434A1 (en) * | 1972-09-27 | 1974-04-19 | Boehler & Co Ag Geb | Pneumatic percussion drill hammer - with grooves as air vent channels on same side of hammer |
AU450556B2 (en) * | 1973-01-09 | 1974-07-11 | "improvements in rock drill bits" | |
US3866746A (en) * | 1973-08-27 | 1975-02-18 | Bakerdrill Inc | Rotary bore hole air hammer drive mechanism |
US3991834A (en) * | 1975-07-07 | 1976-11-16 | Curington Alfred R | Sampling airhammer apparatus |
Also Published As
Publication number | Publication date |
---|---|
EP0003103A3 (en) | 1979-08-08 |
FI69183B (en) | 1985-08-30 |
EP0003103B2 (en) | 1986-12-10 |
FI790023A (en) | 1979-07-07 |
AU4314779A (en) | 1979-07-12 |
NO151016B (en) | 1984-10-15 |
ZA7891B (en) | 1979-08-29 |
FI69183C (en) | 1985-12-10 |
NO790011L (en) | 1979-07-09 |
EP0003103B1 (en) | 1982-12-22 |
AU522330B2 (en) | 1982-05-27 |
NO151016C (en) | 1985-01-23 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4185706A (en) | Rock bit with cavitating jet nozzles | |
US4299298A (en) | Down-the-hole drilling | |
US4687067A (en) | Crossflow rotary cone rock bit with extended nozzles | |
US4723612A (en) | Bit, nozzle, cutter combination | |
WO1997034072A1 (en) | Rock drill bit and a rock drilling tool | |
CA1095502A (en) | Enhanced cross-flow with two jet drilling | |
EP1454029A4 (en) | Fluid drilling head | |
US6581702B2 (en) | Three-cone rock bit with multi-ported non-plugging center jet nozzle and method | |
US4665999A (en) | Variable length three-cone rock bit nozzles | |
US2885186A (en) | Drill bit | |
EP0003103A2 (en) | Down-the-hole drill | |
US2104823A (en) | Cutter flushing device | |
JPS6043516B2 (en) | Body structure of rotary drill bit device and nozzle device for drilling fluid | |
SE516116C2 (en) | Lowering hammer and drill bit | |
CA1097333A (en) | Down-the-hole drilling | |
US4077482A (en) | Three cone rock bit | |
US3420324A (en) | Air rotary drill bit | |
KR200373395Y1 (en) | Bit for Hamma Drill | |
US2969846A (en) | Percussive drill bit for use in reverse flow flushing in soft rock drilling | |
WO1999002815A8 (en) | Device and method for creating ramifications in a bore hole | |
US2335929A (en) | Roller bit | |
CA1094049A (en) | Drill bit for rock drilling | |
US3521716A (en) | Drill point | |
US3452832A (en) | Rock drill bit | |
US2602641A (en) | Drill bit |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
AK | Designated contracting states |
Designated state(s): CH DE FR GB IT NL SE |
|
AK | Designated contracting states |
Designated state(s): CH DE FR GB IT NL SE |
|
17P | Request for examination filed | ||
ITF | It: translation for a ep patent filed |
Owner name: JACOBACCI & PERANI S.P.A. |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Designated state(s): CH DE FR GB IT NL SE |
|
ET | Fr: translation filed | ||
REF | Corresponds to: |
Ref document number: 2964335 Country of ref document: DE Date of ref document: 19830127 |
|
PLBI | Opposition filed |
Free format text: ORIGINAL CODE: 0009260 |
|
26 | Opposition filed |
Opponent name: SANDVIK AKTIEBOLAG Effective date: 19830411 |
|
PLBI | Opposition filed |
Free format text: ORIGINAL CODE: 0009260 |
|
26 | Opposition filed |
Opponent name: FRIED. KRUPP GMBH Effective date: 19830910 |
|
ITF | It: translation for a ep patent filed |
Owner name: JACOBACCI & PERANI S.P.A. |
|
PUAH | Patent maintained in amended form |
Free format text: ORIGINAL CODE: 0009272 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: PATENT MAINTAINED AS AMENDED |
|
27A | Patent maintained in amended form |
Effective date: 19861210 |
|
AK | Designated contracting states |
Kind code of ref document: B2 Designated state(s): CH DE FR GB IT NL SE |
|
NLR2 | Nl: decision of opposition | ||
ET3 | Fr: translation filed ** decision concerning opposition | ||
NLR3 | Nl: receipt of modified translations in the netherlands language after an opposition procedure | ||
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: CH Payment date: 19881208 Year of fee payment: 11 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 19881230 Year of fee payment: 11 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 19890102 Year of fee payment: 11 |
|
ITTA | It: last paid annual fee | ||
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: SE Payment date: 19890131 Year of fee payment: 11 Ref country code: NL Payment date: 19890131 Year of fee payment: 13 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 19890228 Year of fee payment: 11 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Effective date: 19900102 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SE Effective date: 19900103 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: CH Effective date: 19900131 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Effective date: 19900801 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee | ||
NLV4 | Nl: lapsed or anulled due to non-payment of the annual fee | ||
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Effective date: 19900928 |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Effective date: 19901002 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |
|
EUG | Se: european patent has lapsed |
Ref document number: 79100010.2 Effective date: 19901106 |