CA1140226A - Core lamination for shell-type cores, particularly for transformers - Google Patents
Core lamination for shell-type cores, particularly for transformersInfo
- Publication number
- CA1140226A CA1140226A CA000317286A CA317286A CA1140226A CA 1140226 A CA1140226 A CA 1140226A CA 000317286 A CA000317286 A CA 000317286A CA 317286 A CA317286 A CA 317286A CA 1140226 A CA1140226 A CA 1140226A
- Authority
- CA
- Canada
- Prior art keywords
- width
- yoke
- core laminations
- center leg
- laminations
- 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
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/24—Magnetic cores
- H01F27/245—Magnetic cores made from sheets, e.g. grain-oriented
Abstract
Abstract of the Disclosure Core laminations of two piece EI construction for shell-type cores comprising an E part providing three legs 1,2,3 and a yoke 5, and an I part providing a yoke 4, the width c1 of the yoke 5 being greater than the width c2 of the yoke 4, the width b of the outer legs is greater than half the width f of the middle leg, and the sum C1 + c2 is greater than f. In the stacked core the E and I parts may be in respective stacks, or alternate layers may be reversed. The laminations may be secured by cementing, welding or clamping. The arrangement permits nearly wasteless stamping and improved electrical and magnetic characteristics.
Description
114~Z26 Core Lamination for Shell~type cores, particularly for Transformers.
__.__ _ The invention relates to imp~ovements in magnetic core laminations of two piece EI configuration providing three legs and two end yokes, for shell type magnetic cores utilizing a plurality of said EI laminations provided in layers, said layers being provided with an E
and an I part, the E parts having a center leg and two outer legs parallel thereto at a distance and an integral yoke, which will be called the integral yoke and the ends of said legs abut one side of the I parts, constituting the other yoke, which will be called the separated yoke, and wherein lower reluctance, reduced magnetic leakage and higher efficiency is achieved by means which are described hereafter.
Namely, in addition to the so-called M type of core laminations for shell-type cores, there is also another very widely used type, namely the so-called EI core lamination, for instance according to US-Patent 3,546,571;
~th December 1970; USA Fletcher et al. Core laminations o~ the EI type are distinguished in particular by very economical manuacture because they can be stamped with litt'le or no waste at al], and I parts being obtained from the waste left after the E parts have been stamped.
By far the greatest majority of known art magnetic core laminations for shell-type cores of two piece EI
construction are provided with a ratio of the center leg width being twice the width of'each outer leg and also twice the width of each of th~ end yokes which are of the same width as the outer legs, that is half the center leg width.
It is the object of the invention to provide new and improved magnetic core laminations of two piece EI
construction, so that a core comprising such lam;nations will be characterised by lower reluctance, reduced maynetic leakage and higher efficiency.
According to the invention this object is achieved by ~roviding a core laminations comprising an E
11~()226 pa,rt .~nd ,3,n :I: p3rt;, . r,a.rts and I
parts b-^in~r,~orned hy ,i.-~u].tareous stampin-,-to minimize ~aste9 ~rovidin, t'n-~e l,e rS end t~ o end -~rokDs and quita.bl.D
for ,hell-typa m.~,net~c coresf -~arti,cularly for transformer--"
the -~ rt havin-~, a Crnter 1 ~? r and tl~,o outer le rS ~arallel t,hereto at ~1 di.,tance ~nd an interra.l yoke, ~hich ;~7ilL be called the interral ~Joke, .r.d the ends o.f .-,aid le-rs a.butti,n r one side of the '~ par-t con.,ti,tutinr~ the other ~olce9 whi.ch .~;ill be called the ~se~r,ltrd ~olA~e~ characterised in that the width (cl) o.f saicl inte,rral yoke i.s rreater tha.n the ~ridth (c2) of said se~arated yokr, (cl ~c2) and -rreater -than half the center ler~idth (cl~f'/2) and the width (b) of the two outer le rs i5 ~,reater than half the center le r I~Jidth (b ~f~2).
I~oreover, these rneasures not only suppl~y an advantageous .,olution -to the ,iven prob]em, but also provide core laminations of ~uite reneral, applicati.on. ~tacked alternately, these core la.minations yield transformers o.f much improved marnetic and electrical characteri,tics;
and stacked in the same direction, they can be used to advantaTe to make weldecl cores, cemented cores or clamped cores. rhis a;~r)lies particularly to EI laminations ~hen the width of the inte,.rral yol,ce is rreater than half the cent~r l,e r ~idth9 preferabl~ hen the su~n of the ~idths of the two yokes is at least 1.3 times, maximlm l.L~ times the center le-~ idth and the outer le~ idth is at least 1.2 ti.mes7 maxi.mum 1.3 times hal:f the cen~er le~ idth. ,,~ 5,'' increase o:f the width o:f the i,nte,-r,ral yoke with refererce to the width of the se~arated yoke yields fair resul,ts, a 1~-,.,~ increase yields -,ood results, a 2'~ i,ncrease yields exce1,lent results.
.~n embodiment of the invention is re~resert~d d;.~r,rlmm,~t;.~,~.l.'.~r ir. t,he dra~in^r, in ~Ihich:
'~ir,. 1 is the ~lan vi.el,~/ of one laver of '.~:;l core laminations~
~; r,. 2 i 5 the plan vie~ of a ,,hell-t,r~e core cons;,stin~ of ,ernatel-y staclce,d El core lamin-ltions.
i~i r,. 3 sho~s the sheJ.l- t~Tl~e core accordin-r, to ~ r,~ ~
J..ockin-r".n the direction of arrow III in ?i-~r. 2.
rhe embodir1ent accordin, to ~i-r,. 1 sholJs a layer of ,o-cal] ed r core 1,~ i.nat,i.ons f~riron cores ln shell.-t~ P
~,ran:,:rormers or thP li'.~.e con~,i.C,tinr of an ~' ~art ,A, l~`.'hi.Ch ..1 _ 114(~226 has a yoke 5, a center leg 1 and two outer legs 2 and 3 width of the yoke ~ which forms t-he I part B. This means that the window widt'n h is e~ual to or greater than the width c2 of the I part B because this is the only possibility of obtaining the I parts B from tne window parts stamped out of the E parts A and hence of cutting the stamping waste to a minimum. Two E parts A are stamped simu]taneously, with their legs pointing toward one another, so that the two window stampings, i.e. the two I parts B, will be of the necessary length. Thus the waste amounts to no more than twice the window length e minus the length a of the I part B of the free yoke 4.
The integral yo~e 5 of the E part A holds the legs 1, ~ and 3 together, its width cl being greater than the width c2 of the separated yoke 4, i.e. the I part B.
The width of the two outer legs 2 and 3 and of the two yokes 4 and 5 is greater than half the width f/2 of the center leg 1. The width b of the outer legs 2 and 3 is preferably 1.2 to 1.3 times half the width f/2 of the center leg 1 whereas the sum of the widths cl and c2 of the two yokes 4 and 5 amounts to 1.3 to 1.4 times the width f of the center leg 1.
The center leg 1, the two outer legs 2 and 3 and the two yokes 4 and 5 enclose the windows 10 and 11, being of window length e calculated in the direction of the longitudinal axis 9 of the center leg 1.
The windows 10 and 11 are asynunetrical to the transverse axis 6 because the width c1 of the integral yoke S is greater than the width c2 of the separated yoke 4, i.e. the I part B.-The shell-type core according to Fig. 2 and 3 contains core ]aminations according to Fig. 1, said core laminations being stacked alternately. The inside edges 12 of the integral yoke 5 of the E parts A are in contact with the winding and its supporting coil form respectively.
Said winding and coil form are not shown in the drawings.
In contrast, the inside edges 15 of the separated yoke 4, i.e. the I parts B are spaced away from the winding and its coil form respectively; by an amount corresponding to tlle yoke width dirference cl - c2. The inside length eK
of the windows in the shell-type core is shorter, by the yoke width difference cl - c2, than the length e of the windows 10 and 11 of the individual core laminations. This form of stacking the core laminations serves to modify the poor, separated yoke cross-section in favour of the heneficial, integral yoke cross-section, without any substantial disadvantage having to be taken into account.
There is no change in the amount of material, stacking time, yoke cross-section or coil form.
In a core comprising ~ alternately stacked laminations of the above kind, the abutting joints are located within the yokes so that some of the magnetic flux can flow out of the yoke in an undivided stream before it even reaches the abutting joints, so diminishing the adverse influence due to said joints. This influence is diminished still further by making the outer legs wider than half the center leg.
It is also possible to stack the EI laminations of the invention in the same direction in the core, the E
parts A and I parts B then being cemented, clamped or welded together after the insertion of the winding and its supporting coil form, respectively. This procedure is particularly adopted in cases where the benefits to the manufacturing process have priority over the electrical characteristics. ~lere again, advantages are obtained by using the core laminations according to the invention.
The magnetic leakage of a shell-type core constructed thus is very low at the end with the integral yokes, firstly because the latter is of larger cross-section and hence of lower reluctance and secondly because all the abutting joints are situated at the other end in the separated yoke part of the shell-type core.
The invention thus provides magnetic core laminations cornprising of two piece EI configuration, wllich are of really universal application, which according to the invention, will be suitable for practically all purposes.
_ ,~_
__.__ _ The invention relates to imp~ovements in magnetic core laminations of two piece EI configuration providing three legs and two end yokes, for shell type magnetic cores utilizing a plurality of said EI laminations provided in layers, said layers being provided with an E
and an I part, the E parts having a center leg and two outer legs parallel thereto at a distance and an integral yoke, which will be called the integral yoke and the ends of said legs abut one side of the I parts, constituting the other yoke, which will be called the separated yoke, and wherein lower reluctance, reduced magnetic leakage and higher efficiency is achieved by means which are described hereafter.
Namely, in addition to the so-called M type of core laminations for shell-type cores, there is also another very widely used type, namely the so-called EI core lamination, for instance according to US-Patent 3,546,571;
~th December 1970; USA Fletcher et al. Core laminations o~ the EI type are distinguished in particular by very economical manuacture because they can be stamped with litt'le or no waste at al], and I parts being obtained from the waste left after the E parts have been stamped.
By far the greatest majority of known art magnetic core laminations for shell-type cores of two piece EI
construction are provided with a ratio of the center leg width being twice the width of'each outer leg and also twice the width of each of th~ end yokes which are of the same width as the outer legs, that is half the center leg width.
It is the object of the invention to provide new and improved magnetic core laminations of two piece EI
construction, so that a core comprising such lam;nations will be characterised by lower reluctance, reduced maynetic leakage and higher efficiency.
According to the invention this object is achieved by ~roviding a core laminations comprising an E
11~()226 pa,rt .~nd ,3,n :I: p3rt;, . r,a.rts and I
parts b-^in~r,~orned hy ,i.-~u].tareous stampin-,-to minimize ~aste9 ~rovidin, t'n-~e l,e rS end t~ o end -~rokDs and quita.bl.D
for ,hell-typa m.~,net~c coresf -~arti,cularly for transformer--"
the -~ rt havin-~, a Crnter 1 ~? r and tl~,o outer le rS ~arallel t,hereto at ~1 di.,tance ~nd an interra.l yoke, ~hich ;~7ilL be called the interral ~Joke, .r.d the ends o.f .-,aid le-rs a.butti,n r one side of the '~ par-t con.,ti,tutinr~ the other ~olce9 whi.ch .~;ill be called the ~se~r,ltrd ~olA~e~ characterised in that the width (cl) o.f saicl inte,rral yoke i.s rreater tha.n the ~ridth (c2) of said se~arated yokr, (cl ~c2) and -rreater -than half the center ler~idth (cl~f'/2) and the width (b) of the two outer le rs i5 ~,reater than half the center le r I~Jidth (b ~f~2).
I~oreover, these rneasures not only suppl~y an advantageous .,olution -to the ,iven prob]em, but also provide core laminations of ~uite reneral, applicati.on. ~tacked alternately, these core la.minations yield transformers o.f much improved marnetic and electrical characteri,tics;
and stacked in the same direction, they can be used to advantaTe to make weldecl cores, cemented cores or clamped cores. rhis a;~r)lies particularly to EI laminations ~hen the width of the inte,.rral yol,ce is rreater than half the cent~r l,e r ~idth9 preferabl~ hen the su~n of the ~idths of the two yokes is at least 1.3 times, maximlm l.L~ times the center le-~ idth and the outer le~ idth is at least 1.2 ti.mes7 maxi.mum 1.3 times hal:f the cen~er le~ idth. ,,~ 5,'' increase o:f the width o:f the i,nte,-r,ral yoke with refererce to the width of the se~arated yoke yields fair resul,ts, a 1~-,.,~ increase yields -,ood results, a 2'~ i,ncrease yields exce1,lent results.
.~n embodiment of the invention is re~resert~d d;.~r,rlmm,~t;.~,~.l.'.~r ir. t,he dra~in^r, in ~Ihich:
'~ir,. 1 is the ~lan vi.el,~/ of one laver of '.~:;l core laminations~
~; r,. 2 i 5 the plan vie~ of a ,,hell-t,r~e core cons;,stin~ of ,ernatel-y staclce,d El core lamin-ltions.
i~i r,. 3 sho~s the sheJ.l- t~Tl~e core accordin-r, to ~ r,~ ~
J..ockin-r".n the direction of arrow III in ?i-~r. 2.
rhe embodir1ent accordin, to ~i-r,. 1 sholJs a layer of ,o-cal] ed r core 1,~ i.nat,i.ons f~riron cores ln shell.-t~ P
~,ran:,:rormers or thP li'.~.e con~,i.C,tinr of an ~' ~art ,A, l~`.'hi.Ch ..1 _ 114(~226 has a yoke 5, a center leg 1 and two outer legs 2 and 3 width of the yoke ~ which forms t-he I part B. This means that the window widt'n h is e~ual to or greater than the width c2 of the I part B because this is the only possibility of obtaining the I parts B from tne window parts stamped out of the E parts A and hence of cutting the stamping waste to a minimum. Two E parts A are stamped simu]taneously, with their legs pointing toward one another, so that the two window stampings, i.e. the two I parts B, will be of the necessary length. Thus the waste amounts to no more than twice the window length e minus the length a of the I part B of the free yoke 4.
The integral yo~e 5 of the E part A holds the legs 1, ~ and 3 together, its width cl being greater than the width c2 of the separated yoke 4, i.e. the I part B.
The width of the two outer legs 2 and 3 and of the two yokes 4 and 5 is greater than half the width f/2 of the center leg 1. The width b of the outer legs 2 and 3 is preferably 1.2 to 1.3 times half the width f/2 of the center leg 1 whereas the sum of the widths cl and c2 of the two yokes 4 and 5 amounts to 1.3 to 1.4 times the width f of the center leg 1.
The center leg 1, the two outer legs 2 and 3 and the two yokes 4 and 5 enclose the windows 10 and 11, being of window length e calculated in the direction of the longitudinal axis 9 of the center leg 1.
The windows 10 and 11 are asynunetrical to the transverse axis 6 because the width c1 of the integral yoke S is greater than the width c2 of the separated yoke 4, i.e. the I part B.-The shell-type core according to Fig. 2 and 3 contains core ]aminations according to Fig. 1, said core laminations being stacked alternately. The inside edges 12 of the integral yoke 5 of the E parts A are in contact with the winding and its supporting coil form respectively.
Said winding and coil form are not shown in the drawings.
In contrast, the inside edges 15 of the separated yoke 4, i.e. the I parts B are spaced away from the winding and its coil form respectively; by an amount corresponding to tlle yoke width dirference cl - c2. The inside length eK
of the windows in the shell-type core is shorter, by the yoke width difference cl - c2, than the length e of the windows 10 and 11 of the individual core laminations. This form of stacking the core laminations serves to modify the poor, separated yoke cross-section in favour of the heneficial, integral yoke cross-section, without any substantial disadvantage having to be taken into account.
There is no change in the amount of material, stacking time, yoke cross-section or coil form.
In a core comprising ~ alternately stacked laminations of the above kind, the abutting joints are located within the yokes so that some of the magnetic flux can flow out of the yoke in an undivided stream before it even reaches the abutting joints, so diminishing the adverse influence due to said joints. This influence is diminished still further by making the outer legs wider than half the center leg.
It is also possible to stack the EI laminations of the invention in the same direction in the core, the E
parts A and I parts B then being cemented, clamped or welded together after the insertion of the winding and its supporting coil form, respectively. This procedure is particularly adopted in cases where the benefits to the manufacturing process have priority over the electrical characteristics. ~lere again, advantages are obtained by using the core laminations according to the invention.
The magnetic leakage of a shell-type core constructed thus is very low at the end with the integral yokes, firstly because the latter is of larger cross-section and hence of lower reluctance and secondly because all the abutting joints are situated at the other end in the separated yoke part of the shell-type core.
The invention thus provides magnetic core laminations cornprising of two piece EI configuration, wllich are of really universal application, which according to the invention, will be suitable for practically all purposes.
_ ,~_
Claims (14)
1) Core laminations of two piece EI configuration comp-rising an E part and an I part, two said I parts being obtained from the window stampings of two E parts stamped simultaneously with the legs pointing toward one another, providing three legs and two end yokes and suitable for shell-type magnetic cores, particularly for transformers utilizing a plurality of said laminations provided in layers, the E part having a center leg and two outer legs parallel thereto at a distance and an integral yoke, which will be called the integral yoke, and the ends of said legs abutting one side of the I part constituting the other yoke, which will be called the separated yoke, characterized in that the width (c1) of said integral yoke is greater than the width (c2) of said separated yoke (c1 > c2) and greater than half the center leg width (c1 > f/2) and the width (b) of the two outer legs is greater than half the center leg width (b>f/2).
2) Core laminations of two piece EI configuration comp-rising an E part and I part, windows being provided for the insertion of a coil-form and winding, providing three legs and two end yokes and suitable for shell-type magnetic cores, particularly for transformers utilizing a plurality of said laminations provided in alternatingly reversed layers, the E
part having a center leg and two outer legs parallel thereto at a distance and an integral yoke, which will be called the integral yoke and which is provided with inside edges facing said windows, and the ends of said legs forming abutting joints with one side of the I part constituting the other yoke, which will be called the separated yoke and which is provided with inside edges facing said windows, characterized in that the width (c1) of said integral yoke is greater than the width (c2) of said separated yoke (c1 > c2) and greater than half the center leg width (c1 > f/2) and the width (b) of the two outer legs is greater than half the center leg width (b > f/2) and wherein in said laminations provided in alternately reversed layers, said inside edges of said separated yoke being spaced away from said coil-form and winding in contrast to said inside edges of said integral yoke, with the inside edges of said separated yoke spaced away from said inside edges of said integral yoke and said integral yoke inner edges nearer the coil-form and winding than said inside edges of said separated yoke and said abutting joints are located inside the yokes of said shell-type core.
part having a center leg and two outer legs parallel thereto at a distance and an integral yoke, which will be called the integral yoke and which is provided with inside edges facing said windows, and the ends of said legs forming abutting joints with one side of the I part constituting the other yoke, which will be called the separated yoke and which is provided with inside edges facing said windows, characterized in that the width (c1) of said integral yoke is greater than the width (c2) of said separated yoke (c1 > c2) and greater than half the center leg width (c1 > f/2) and the width (b) of the two outer legs is greater than half the center leg width (b > f/2) and wherein in said laminations provided in alternately reversed layers, said inside edges of said separated yoke being spaced away from said coil-form and winding in contrast to said inside edges of said integral yoke, with the inside edges of said separated yoke spaced away from said inside edges of said integral yoke and said integral yoke inner edges nearer the coil-form and winding than said inside edges of said separated yoke and said abutting joints are located inside the yokes of said shell-type core.
3) Core laminations as defined in claim 1 characterized in that the sum of the widths (c1 + c2) of the yokes is at least 1.3 times and maximum 1.4 times the center leg width (f).
4) Core laminations as defined in claim 1 or claim 3 charac-terized in that the outer legs width (b) is at least 1.2 times and maximum 1.3 times half the center leg width (f/2).
5) Core laminations as defined in claim 2 characterized in that the outer legs width (b) is at least 1.2 times and maximum 1.3 times half the center leg width (f/2).
6) Core laminations as defined in claim 1 or 2 or 5 characterized in that the width (c1) of the integral yoke is at least 5% greater than the width (c2) of the separated yoke.
7) Core laminations as defined in claim1 or 2 or 5 char-acterized in that the width of the integral yoke (c1) is at least 10% greater than the width of the separated yoke(c2).
8) Core laminations as defined in claim 1 or 2 or 5 charac-terized in that the width of the integral yoke (c1) is at least 20% greater than the width (c2) of the separated yoke.
9) Core laminations as defined in claim 1 or 2 or 5 charac-terized in that the distance (h) between each outer leg and the center leg is equal to the width (c2) of the I part (B).
10) Core laminations as defined in claim 1 or 2 or 5 charac-terized in that the distance (h) between each outer leg and the center leg is greater than the width (c2) of the I part (b) (h > c2).
11) Core laminations as defined in claim 2 or 5 characterized in that the waste during stamping amounts to no more than twice, the length (e)of the windows minus the length (a) of the I part (B) of the separated yoke.
12) Core laminations as defined in claim 1 or 2 or 5 charac-terized in that the width (c2) of the separated yoke is greater than half the center leg width (f/2).
13) Core laminations as defined in claim 1 or 2 or 5 charac-terized in that the width (c2) of the separated yoke is at least half the center leg width (f/2).
14) Core laminations as defined in claim 2 or 5 characterized in that a plurality of said layers of core laminations are interleaved in an alternatingly opposite direction so that the inside length (eK) of the windows is shorter, by the difference of the yoke widths (c1 - c2) than the length (e) of the windows of the individual core laminations.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19772755218 DE2755218A1 (en) | 1977-12-10 | 1977-12-10 | CORE SHEET FOR SHELL, IN PARTICULAR FOR TRANSFORMERS |
| DEP2755218.7 | 1977-12-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1140226A true CA1140226A (en) | 1983-01-25 |
Family
ID=6025877
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000317286A Expired CA1140226A (en) | 1977-12-10 | 1978-12-04 | Core lamination for shell-type cores, particularly for transformers |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS5480515A (en) |
| AU (1) | AU532260B2 (en) |
| CA (1) | CA1140226A (en) |
| DE (1) | DE2755218A1 (en) |
| GB (1) | GB2016816B (en) |
| IT (2) | IT7869796A0 (en) |
| MX (1) | MX145428A (en) |
| MY (1) | MY8600726A (en) |
| NZ (1) | NZ188767A (en) |
| SG (1) | SG60685G (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2920365A1 (en) * | 1979-05-19 | 1980-11-27 | Philberth Karl Dr Phys | CORE SHEET FOR SHELL CORES, ESPECIALLY FOR TRANSFORMERS |
| DE3005567A1 (en) * | 1980-02-14 | 1981-08-20 | Philberth, Karl, Dr.-Phys., 8031 Puchheim | CORE SHEETS, ESPECIALLY FOR TRANSFORMERS |
| JPS62138426U (en) * | 1986-02-24 | 1987-09-01 | ||
| JPH04212403A (en) * | 1990-01-25 | 1992-08-04 | Branimir Jakovljevic | Magnetic core sheet |
| JP2008277010A (en) * | 2007-04-26 | 2008-11-13 | Fuji Electric Fa Components & Systems Co Ltd | Electromagnetic contactor |
-
1977
- 1977-12-10 DE DE19772755218 patent/DE2755218A1/en not_active Withdrawn
-
1978
- 1978-09-29 AU AU40328/78A patent/AU532260B2/en not_active Expired
- 1978-10-02 GB GB7838892A patent/GB2016816B/en not_active Expired
- 1978-10-30 NZ NZ188767A patent/NZ188767A/en unknown
- 1978-11-15 JP JP13994578A patent/JPS5480515A/en active Granted
- 1978-12-04 CA CA000317286A patent/CA1140226A/en not_active Expired
- 1978-12-06 IT IT7869796A patent/IT7869796A0/en unknown
- 1978-12-06 IT IT7853955U patent/IT7853955V0/en unknown
- 1978-12-08 MX MX175926A patent/MX145428A/en unknown
-
1985
- 1985-08-16 SG SG606/85A patent/SG60685G/en unknown
-
1986
- 1986-12-30 MY MY726/86A patent/MY8600726A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DE2755218A1 (en) | 1979-06-13 |
| GB2016816A (en) | 1979-09-26 |
| NZ188767A (en) | 1981-12-15 |
| JPS641923B2 (en) | 1989-01-13 |
| AU532260B2 (en) | 1983-09-22 |
| MX145428A (en) | 1982-02-08 |
| JPS5480515A (en) | 1979-06-27 |
| IT7853955V0 (en) | 1978-12-06 |
| MY8600726A (en) | 1986-12-31 |
| AU4032878A (en) | 1980-04-03 |
| IT7869796A0 (en) | 1978-12-06 |
| SG60685G (en) | 1987-03-27 |
| GB2016816B (en) | 1982-08-18 |
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