US3351006A - Print hammer having braking means - Google Patents

Print hammer having braking means Download PDF

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Publication number
US3351006A
US3351006A US374339A US37433964A US3351006A US 3351006 A US3351006 A US 3351006A US 374339 A US374339 A US 374339A US 37433964 A US37433964 A US 37433964A US 3351006 A US3351006 A US 3351006A
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US
United States
Prior art keywords
hammer
print
rest position
damping
hammers
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 - Lifetime
Application number
US374339A
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English (en)
Inventor
Ross A Belson
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.)
Honeywell Inc
Original Assignee
Honeywell Inc
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 Honeywell Inc filed Critical Honeywell Inc
Priority to US374339A priority Critical patent/US3351006A/en
Priority to GB13732/65A priority patent/GB1103732A/en
Priority to NO157904A priority patent/NO115722B/no
Priority to CH720265A priority patent/CH439344A/fr
Priority to BE664450D priority patent/BE664450A/xx
Priority to FR18604A priority patent/FR1436361A/fr
Priority to DEH56166A priority patent/DE1279983B/de
Priority to FI651297A priority patent/FI47020C/fi
Priority to SE7485/65A priority patent/SE314546B/xx
Priority to NL6507314A priority patent/NL6507314A/xx
Priority to AT529665A priority patent/AT261264B/de
Priority to DK293165AA priority patent/DK122215B/da
Application granted granted Critical
Publication of US3351006A publication Critical patent/US3351006A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J9/00—Hammer-impression mechanisms
    • B41J9/42—Hammer-impression mechanisms with anti-rebound arrangements

Definitions

  • the print hammer is spring-biased to the rest position into contact with an actuator arm that abuts a back stop.
  • the actuator arm By energizing the actuator arm, the print hammer is propelled forward against the moving type carrier, from which it rebounds to return to its rest position, in part under the influence of the biasing springs.
  • the hammer return normally occurs at a high velocity so as to cause further rebounding when the rear impact surface of the print hammer meets the actuator arm.
  • the second rebound isin a forward direction and, if sufliciently large, may cause shadow printing or ghosting on the paper.
  • the flight time of the print hammer, and hence its arrival at the type carrier will be different and will result in a positional variation of the printed character from the norm.
  • the type carrier is a rotating type roll whose raised characters move columnarly past each print hammer at the print station, any variation of the flight time of the latter will result in the printing of the character above or below the print line.
  • the type carrier is in the form of a chain or belt which moves parallel to the aligned row of print hammers at the print station, variations in the flight time of a print hammer will result in a variable positioning of the printed character along the print line.
  • a further disadvantage derives from the fact that no control over the damping characteristics can be exer cisedonce the elastic material is installed. For example, if it is necessary to exchange the hammers there may be sufficient difference in their characteristics to require a changein the amount of damping required. Where an elastic damping material is used behind each, back stop,
  • FIGURES 1A and 1B illustrate a preferred embodiment of the present invention
  • FIGURES 2A and 2B illustrate another embodiment of the invention.
  • the print hammer 10 is seen to have a forward section 16 and a. rear section 18 connected by a central shank 20. All portions of the print hammer are of uniform thickness.
  • the forward print hammer section terminates in a concave striking surface 22 which faces the type characters 14 as they rotate past the print station.
  • the rear hammer section 18 terminates in a convex impact surface 24 which, when the hammer 10 is in the rest position shown in FIGURE 1A, abuts an actuator arm 26. The latter in turn rests against a fixed back stop 28.
  • the hammer 10 is supported on a pair of leaf springs 30 which are aflixed to the hammer front and rear sections respectively, as well as to a fixed hammer support 32.
  • the actuator arm 26 is rotatably disposed about a pivot 34, the lower arm portion facing a solenoid 36.
  • a signal S may be selectively applied to the terminals of a solenoid winding 38.
  • the front and rear hammer sections 16 and 18 respectively further include a pair of planar raised surfaces 49 and 42 respectively, which project above the corresponding surf-ace 21 of the shank 20.
  • a horse shoe electromagnet 44 is positioned to one side of the print hammer 20 and has a pair of pole faces 46 and 48.
  • the configuration of the pole face 46 is such that, in the rest position of the print hammer, it is positioned opposite the front sect-ion surface 40 to define a gap 47 therebetween of substantially uniform width.
  • the pole face 48 is positioned opposite the rear hammer surface 42 to define a uniform gap 49 of substantially the same width as the gap 47.
  • a signal source 51 is connected across the terminals of a winding 53 of the magnet 44 and is selectively adapted to provide an under-damped current waveform 55, as shown in FIGURE 1A.
  • the applied signal may be varied as to amplitude and duration to obtain the desired damping characteristics.
  • FIGURE 1A The arrangement illustrated in FIGURE 1A is substantially repeated 132 times in the preferred embodiment of the invention, with respective print hammers aligned in a row side by side.
  • Each print hammer is supported on a pair of leaf springs and sufficient clearance exists between them to permit hammer movement.
  • a single magnet 44 is preferably employed, which runs the length of the entire row of print hammers, so that successive print hammers are positioned opposite different portions of the same pair of pole faces 46 and 4-8.
  • Each support 32 may either carry a single print hammer, or a modular arrangement may be used wherein more than one print hammer is carried by a single support.
  • the actuator arms 26 of successively positioned print hammers may alternately extend from above and below in FIGURE 1A, so as to obtain the requisite spacing to accommodate each solenoid 36.
  • the convex impact surface 24 is in contact with the actuator arm 26, which in turn rests against the fixed back stop 28.
  • the leaf springs 30 are either perpendicular to the support 32 in the rest position, or they are tilted slightly in a forward direction, i.e. toward the type roll 12, in order to apply the requisite bias to the print hammer 10 to urge it to the rest position.
  • the spacing of the concave hammer striking surface 22 from the raised characters 14 in the hammer rest position is determined by the number of copies to be printed simultaneously which, together with interleaved sheets of carbon paper and an inked ribbon, must be accommodated therebetween.
  • the corresponding actuator arm 26 When a signal S is applied to the winding 38 of any solenoid 36 during the print cycle, the corresponding actuator arm 26 is attracted and pivots forward about its pivot pin 34.
  • the movement of the actuator arm 26 is limited so that the print hammer 10 travels forward toward the type roll 12 under its own momentum and at high velocity to drive the intermediately positioned paper and ribbon against the latter.
  • the hammer Upon rebounding off the type roll, the hammer returns toward its rest position, to which it is urged by the leaf springs 30. In its rearward travel, the hammer 10 also returns the actuator 26 into contact with the back stop 28.
  • a damping signal having an underdamped waveform 55, is applied to the magnet winding 53- at the termination of each print cycle.
  • This damping signal sets up a flux path which includes the magnet 44, the hammer 10 and the two flux gaps 47 and 49.
  • the gapbridging flux lines which are indicated by dotted lines, in the drawings, have their minimum length in the hammer rest position shown in FIGURE 1A, so that the overall flux path similarly is at a minimum then.
  • the damping action is controllable in degree and in time by controlling the damping signal which is applied to the winding 53.
  • the maximum amplitude of the applied signal which may be of the order of 3 to 4 amperes, will depend on the desired damping characteristic of the overall arrangement.
  • the damping signal is applied only during the paper feed cycle. Thus, there is no interference with the forward hammer movement during the print cycle.
  • the damping signal being applied immediately following the termination of the preceding print cycle, acts to settle only the hammers which are still oscillating at such time. Those hammers which are actuated early in the print cycle will normally have settled to their rest position at end of the print cycle.
  • the actuator arm 26 is seen to be positioned in close proximity to the aforesaid flux path, but is preferably excluded therefrom for efiicient operation. Accordingly, the arm 26 may consist of stainless steel whose permeability is low compared to the permeability of the hammer 10 which may consist of hardened steel. The end of the actuator arm 26, which is in contact with the hammer impact surface 24, may be treated to lower its permeability still further.
  • FIGURES 2A and 2B illustrate a further embodiment of the present invention, applicable reference numerals having been retained.
  • a toro'id-like magnet 58 is employed whose pole faces 54 and 56 are positioned at right angles to each other. As in the embodiment of FIGURES 1A and 1B, the pole faces 54 and 56 run the entire length of the aligned row of print hammers 10.
  • each print hammer carries a flag 52 consisting of a highpermeability material, which is positioned between the pole faces 54 and 56 in the hammer rest position shown in FIGURE 2A.
  • a pair of uniform gaps 60 and 62 is defined between a pair of mutually perpendicular flag surfaces 57, 59 and the pole faces 54 and 56 respectively.
  • FIGURE 2B illustrates the forward hammer position.
  • the pole face 54 now faces only a portion of the flag surface 57. Accordingly, some of the flux flowing through the pole face 54 now links the surface 59 and another portion of the flux directly links the pole face 56.
  • the width of the pulse gap 60 is therefore non-uniformly increased.
  • the width of the flux gap 62 is greater when the hammer 10 is in its forward position than in the rest position.
  • FIGURE 2 An important advantage of the arrangement illustrated in FIGURE 2 resides in the fact that the print hammer and the actuator arm may be effectively excluded from the magnetic flux path, which now includes only the magnet 58, the gaps 6t and 62 and the flag 52. Since the latter is not subject to the requirements which are applicable to the hammers, it may consist of a high-permeability material so that greater sensitivity is obtained and the damping action is more readily effected.
  • the damping arrangement herein disclosed may find application in chain printers where rapid settling of the hammer oscillations is similarly required.
  • the physical configuration of the hammers may vary, provided only that a projection is provided which is flux-link'ed to a magnetic pole through a variable gap.
  • the hammer itself need not be supported on leaf springs, as shown,
  • a damping mechanism comprising a component movable between two extreme positions, means for resiliently urging said component to one extreme position, means for selectively driving said component to said other extreme position, and means for damping out the oscillations of said component upon its return to said one extreme position, said damping means comprising a magnetically passive projection of relatively high permeability on said component, and magnet means external to said component adapted to provide a mag netic field, said magnet means having at least one magnetic pole positioned opposite said projection and spaced therefrom in said one extreme position to'provide a variable reluctance flux path, including said projection, which has its minimum reluctance in said one extreme position.
  • said magnet means external to said component comprises a magnetic core and an associated winding, and a variable signal source adapted to energize said winding.
  • a print station a type roll rotatably adapted to present diiferent characters to said print station for printing on an intermediately positioned paper web
  • said print station including a plurality of aligned hammers of relatively high permeability each comprising an elongated structure of uniform width having front and rear sections connected by a central shank, said front section having a concave forward surface facing said type roll and spaced therefrom, said rear section having a convex rear surface, said front and rear sections each having parallel upper and lower surfaces lying in a pair of common planes disposed above and below respectively, corresponding surfaces of said central shank, a support parallel to said planes,'a pair of parallel leaf springs transverse to said planes and coupling said bottom surfaces to said support to permit movement of said hammer in a direction substantially parallel to said planes, a magnet including first and second pole faces positioned opposite respective ones of said pair of co-planar upper surfaces in the rest position of said-hammer to define first and second gaps
  • said magnet includes a winding, and a variable signal source adapted to energize said winding.
  • a print station a type carrier movably adapted to present different type characters to said print station for printing on an intermediately positioned paper web
  • said print station comprising a plurality of aligned, elongated print hammers of relatively high permeability each having a striking surface facing said type characters and a rear impact surface, a pair of raised surfaces on one side of each hammer lying in a common plane spaced from the central hammer structure th'erebetween, a pair of spaced leaf springs anchored in the other side of each hammer transverse thereto, said leaf springs being further anchored in a fixed support and permitting substantially linear hammer movement toward said type roll from a resiliently maintained rest position, a magnet disposed on said one side of each hammer and including a pair of pole faces uniformly spaced from and opposite to said raised surfaces when said hammer is in its rest position, and an actuator selectively adapted to strike said rear impact surface to drive saidhammer forward against said type characters, thereby
  • a high-speed printer comprising a platen, a print station including a print hammer resiliently urged to a rest position, means for selectively driving said hammer out of said rest position against said platen to print on an intermediately positioned paper web, means for damping out hammer oscillations upon the return of said hammer to said rest position, said damping means comprising at least one magnetically passive projection of relatively high permeability on said hammer, and magnet means external to said hammer adapted to provide a magnetic field, said magnet means including a magnetic pole positioned opposite said hammer projection and spaced therefrom in the hammer rest position to provide a variable reluctance flux path, including said projection, which has its minimum reluctance in said rest position.
  • a print station a type carrier movably adapted to present different characters to said print station for printing on an intermediately. positioned paper web, said print station comprising a plurality of elongated, aligned hammers each having a striking surface facing said characters, each of said hammers being supported on a pair of transverse leaf springs resiliently urging it to a rearward hammer rest position but permit ting forward hammer movement, means for selectively driving said hammers out or said rest position against said characters, and means for damping out hammer oscillations upon the return of each hammer to its rest position, said damping means comprising at least one magadapted to propel said hammer forward, a back stop, said hammer urging said actuator arm against said back stop in said rest position.
  • each of said actuator arms consists of a material whose permeability is low compared to that of said hammers.
  • said magnet means external to said hammers comprises a magnetic core and an associated winding, and a variable Signal source adapted to energize said winding.
  • each of said hammers includes a pair of projections terminating in a pair of co-planar surfaces spaced from a parallel surface of an intermediately positioned central hammer portion, said magnet means external to said hammers including a pair of magnetic poles terminating in a pair of pole faces positioned opposite respective ones of said pair of coaplanar surfaces to define a pair of gaps of uniform width in said hammer rest position, said forward hammer movement causing the effective width of at least one of said gaps to be non-uniformly increased by bringing said central hammer portion surface at least partly opposite one of said pole faces.
  • a print station a type carrier movably adapted to present different characters to said print station for printing on an intermediately positioned paper web
  • said print station comprising a plurality of elongated, aligned hammers each having a striking surface facing said characters, each of said hammers being supported on a pair of transverse leaf springs resiliently urging it to a rearward hammer rest position but permitting forward hammer movement, means for selectively driving said hammers out of said rest position against said characters, means for damping out hammer oscillations upon the return of each hammer to its rest position, said damping means comprising a substantially toroidal, magnetic core terminating in a pair of mutually perpendicular pole faces, and at least one projecting flag on each hammer including a pair of surfaces substantially parallel to respective ones of said pole faces and uniformly spaced therefrom in said hammer rest position, each of said flags providing a flux path with said core which has its minimum length in said hammer rest
  • a print station a type roll rotatably adapted to present different rows of identical characters to said print station for printing on an intermediately positioned paper web
  • said print station comprising a plurality of elongated print hammers of uniform thickness aligned in a row parallel to the axis of said type roll, each of said hammers including front and rear hammer sections connected by a central shank, said front hammer section having a concave striking surface facing said type roll and upper and lower surfaces spaced respectively above and below corresponding surfaces of said shank, said rear hammer section terminating in a convex impact surface and including upper and lower surfaces coplanar with the corresponding surfaces of said front section, a fixed support spaced from said lower surfaces and parallel thereto, a pair of leaf springs corresponding to each hammer and having their ends anchored in said lowor surfaces and in said support respectively, each pair of leaf springs resiliently urging its hammer to a rest position but permitting forward hammer movement toward
  • said magnet includes a winding and a variable current source selectively adapted to energize said winding.

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US374339A 1964-06-11 1964-06-11 Print hammer having braking means Expired - Lifetime US3351006A (en)

Priority Applications (12)

Application Number Priority Date Filing Date Title
US374339A US3351006A (en) 1964-06-11 1964-06-11 Print hammer having braking means
GB13732/65A GB1103732A (en) 1964-06-11 1965-03-31 Improvements in or relating to high-speed printers
NO157904A NO115722B (xx) 1964-06-11 1965-04-30
CH720265A CH439344A (fr) 1964-06-11 1965-05-24 Machine à imprimer à grande vitesse
BE664450D BE664450A (xx) 1964-06-11 1965-05-25
FR18604A FR1436361A (fr) 1964-06-11 1965-05-26 Machine à imprimer à grande vitesse
DEH56166A DE1279983B (de) 1964-06-11 1965-05-28 Druckhammeraggregat fuer Schnelldrucker
FI651297A FI47020C (fi) 1964-06-11 1965-06-01 Suurinopeuksellinen painokirjoitin.
SE7485/65A SE314546B (xx) 1964-06-11 1965-06-08
NL6507314A NL6507314A (xx) 1964-06-11 1965-06-09
AT529665A AT261264B (de) 1964-06-11 1965-06-11 Schnelldrucker
DK293165AA DK122215B (da) 1964-06-11 1965-06-11 Hurtigskriver.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US374339A US3351006A (en) 1964-06-11 1964-06-11 Print hammer having braking means

Publications (1)

Publication Number Publication Date
US3351006A true US3351006A (en) 1967-11-07

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ID=23476358

Family Applications (1)

Application Number Title Priority Date Filing Date
US374339A Expired - Lifetime US3351006A (en) 1964-06-11 1964-06-11 Print hammer having braking means

Country Status (12)

Country Link
US (1) US3351006A (xx)
AT (1) AT261264B (xx)
BE (1) BE664450A (xx)
CH (1) CH439344A (xx)
DE (1) DE1279983B (xx)
DK (1) DK122215B (xx)
FI (1) FI47020C (xx)
FR (1) FR1436361A (xx)
GB (1) GB1103732A (xx)
NL (1) NL6507314A (xx)
NO (1) NO115722B (xx)
SE (1) SE314546B (xx)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3672482A (en) * 1970-08-31 1972-06-27 Ibm Wire matrix print head
US3707122A (en) * 1970-07-13 1972-12-26 Peripheral Dynamics Print hammer mechanism with magnetic reinforcement to cath hammer
US3834303A (en) * 1973-02-16 1974-09-10 Pertec Corp High speed line printing apparatus
US3878778A (en) * 1972-01-11 1975-04-22 Suwa Seikosha Kk Printer
US3969998A (en) * 1971-11-30 1976-07-20 Compagnie Honeywell Bull (Societe Anonyme) Printing actuator
US4004505A (en) * 1973-11-06 1977-01-25 Compagnie Honeywell Bull (Societe Anonyme) Electromagnetic striker mechanism for a printer
USRE29745E (en) * 1972-01-11 1978-08-29 Shinshu Seiki Kabushiki Kaisha Printer
US4236842A (en) * 1978-08-03 1980-12-02 A. B. Dick Company Hammer support for rotary printing apparatus
US4279520A (en) * 1978-06-19 1981-07-21 International Business Machines Corporation Print mechanism for wire printer
US4348119A (en) * 1980-11-06 1982-09-07 General Electric Company Bounce control system for moving coil printing element
US4392423A (en) * 1978-02-08 1983-07-12 Hitachi, Ltd. Printing hammer driving apparatus
US5153472A (en) * 1991-07-19 1992-10-06 International Business Machines Corporation Probe positioning actuator

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3714892A (en) * 1970-10-20 1973-02-06 Odec Computer Syst Inc Impact hammer for liner printer
US3741113A (en) * 1971-06-25 1973-06-26 Ibm High energy print hammer unit with fast settle out

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2708737A (en) * 1952-06-18 1955-05-17 Weston Electrical Instr Corp Instrument damping system
US2787210A (en) * 1953-01-22 1957-04-02 Jr Francis H Shepard Hammer impelling means in high speed printers
US2788457A (en) * 1953-02-11 1957-04-09 Hughes Aircraft Co Network for damping vibrations of mechanical structures
US2951955A (en) * 1954-12-24 1960-09-06 Crowder John Hardin Vibration dampeners for machine tools
US3072045A (en) * 1958-06-02 1963-01-08 Bull Machines Sa Triggering electronic devices for the control of electromagnetic actuating devices
US3144821A (en) * 1960-10-06 1964-08-18 Ibm Printer apparatus having print force control
US3172352A (en) * 1963-05-13 1965-03-09 Data Products Corp Printing hammer assembly
US3172353A (en) * 1963-06-17 1965-03-09 Data Products Corp Variable force hammer high speed printer
US3199650A (en) * 1961-08-02 1965-08-10 Ibm Hammer with dampening means for high speed printer

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB859914A (en) * 1957-03-20 1961-01-25 Bailey Meters Controls Ltd Improvements in or relating to means for providing a visual indication or record
FR1212331A (fr) * 1958-10-08 1960-03-23 Bull Sa Machines Perfectionnements aux machines imprimantes à roues à caractères en rotation continue
US3049990A (en) * 1960-12-20 1962-08-21 Ibm Print hammer actuator
NL289885A (xx) * 1961-05-01

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2708737A (en) * 1952-06-18 1955-05-17 Weston Electrical Instr Corp Instrument damping system
US2787210A (en) * 1953-01-22 1957-04-02 Jr Francis H Shepard Hammer impelling means in high speed printers
US2788457A (en) * 1953-02-11 1957-04-09 Hughes Aircraft Co Network for damping vibrations of mechanical structures
US2951955A (en) * 1954-12-24 1960-09-06 Crowder John Hardin Vibration dampeners for machine tools
US3072045A (en) * 1958-06-02 1963-01-08 Bull Machines Sa Triggering electronic devices for the control of electromagnetic actuating devices
US3144821A (en) * 1960-10-06 1964-08-18 Ibm Printer apparatus having print force control
US3199650A (en) * 1961-08-02 1965-08-10 Ibm Hammer with dampening means for high speed printer
US3172352A (en) * 1963-05-13 1965-03-09 Data Products Corp Printing hammer assembly
US3172353A (en) * 1963-06-17 1965-03-09 Data Products Corp Variable force hammer high speed printer

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3707122A (en) * 1970-07-13 1972-12-26 Peripheral Dynamics Print hammer mechanism with magnetic reinforcement to cath hammer
US3672482A (en) * 1970-08-31 1972-06-27 Ibm Wire matrix print head
US3969998A (en) * 1971-11-30 1976-07-20 Compagnie Honeywell Bull (Societe Anonyme) Printing actuator
US3878778A (en) * 1972-01-11 1975-04-22 Suwa Seikosha Kk Printer
USRE29745E (en) * 1972-01-11 1978-08-29 Shinshu Seiki Kabushiki Kaisha Printer
US3834303A (en) * 1973-02-16 1974-09-10 Pertec Corp High speed line printing apparatus
US4004505A (en) * 1973-11-06 1977-01-25 Compagnie Honeywell Bull (Societe Anonyme) Electromagnetic striker mechanism for a printer
US4392423A (en) * 1978-02-08 1983-07-12 Hitachi, Ltd. Printing hammer driving apparatus
US4279520A (en) * 1978-06-19 1981-07-21 International Business Machines Corporation Print mechanism for wire printer
US4236842A (en) * 1978-08-03 1980-12-02 A. B. Dick Company Hammer support for rotary printing apparatus
US4348119A (en) * 1980-11-06 1982-09-07 General Electric Company Bounce control system for moving coil printing element
US5153472A (en) * 1991-07-19 1992-10-06 International Business Machines Corporation Probe positioning actuator

Also Published As

Publication number Publication date
AT261264B (de) 1968-04-10
FI47020C (fi) 1973-08-10
FI47020B (xx) 1973-05-02
NL6507314A (xx) 1965-12-13
FR1436361A (fr) 1966-04-22
NO115722B (xx) 1968-11-18
DK122215B (da) 1972-02-07
GB1103732A (en) 1968-02-21
SE314546B (xx) 1969-09-08
BE664450A (xx) 1965-09-16
DE1279983B (de) 1968-10-10
CH439344A (fr) 1967-07-15

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