US2740064A - Permanent magnet focussing device for cathode ray tubes - Google Patents

Permanent magnet focussing device for cathode ray tubes Download PDF

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Publication number
US2740064A
US2740064A US375782A US37578253A US2740064A US 2740064 A US2740064 A US 2740064A US 375782 A US375782 A US 375782A US 37578253 A US37578253 A US 37578253A US 2740064 A US2740064 A US 2740064A
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US
United States
Prior art keywords
cathode ray
permanent magnet
plate
magnets
main support
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
US375782A
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English (en)
Inventor
Birkbeck Guy
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.)
Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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 Hartford National Bank and Trust Co filed Critical Hartford National Bank and Trust Co
Application granted granted Critical
Publication of US2740064A publication Critical patent/US2740064A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/58—Arrangements for focusing or reflecting ray or beam
    • H01J29/64—Magnetic lenses
    • H01J29/68—Magnetic lenses using permanent magnets only

Definitions

  • the invention relates to television receivers or like apparatus of the kind employing a cathode ray tube with permanent magnet focussing of the electron beam.
  • any adjustment of the focussing magnets should be readily available to the user of the receiver as for example a control knob on the front or side of the receiver cabinet.
  • the object of the invention is to provide a simple and efficient focussing mount for permanent magnets of the ceramic type as above defined which is readily controllable from any position convenient to the user of the television or like receiver.
  • a permanent magnet focussing mount for the cathode ray tube of a television receiver or like apparatus comprises a main support member adapted to be accurately located with respect to the cathode ray tube neck, a first permanent magnet of annular form surrounding and coaxially located with respect to the tube neck and secured on an extension of the member and a second permanent magnet of annular form coaxially located with respect to the tube neck and mounted on a secondary support member adapted to be moved relatively to said first magnet and coaxially therewith and a lever fulcrumed on the main support member for moving said secondary support member and controlled in any suitable manner as for example by a Bowden cable.
  • Figure 1 is a side elevation of the focussing mount.
  • Figure 2 is a front elevation of the same.
  • Figure 2A is a cross-sectional view along the line 2A-2A.
  • Figure 3 is a rear view showing the cathode ray tube locating means.
  • the focussing mount comprises a main support member 1 in the form of a metal plate having its long edges bent over to increase the longitudinal rigidity and carrying a pair of guides 2 and 3, to the outer ends of which a plate 4 is attached.
  • This plate has a member of extending tabs 5, for example, three, which are adapted to be bent up against the peripheral wall of an annular permanent magnet 6, so as to hold it securely on the plate.
  • the plate has an aperture for the tube neck as has also the main support member 1.
  • a second annular magnet 7 is secured in a like manner by tabs 8 to an apertured plate 9 which is mounted for movement towards and away from the plate 4 whilst guide 10 secured to the plate 9 engaging the guide 2 wit a sliding fit. Adjacent the guide 3 the plate 9 is slit and apair of guide flanges 11 and 12 ( Figure 2) bent at right angles are arranged to embrace guide 3.
  • Movement of the magnet 7 towards the magnet 6 is efiected by a lever 13 which may be fulcrumed on the plate 1 as by pivot 14.
  • the lever has a forked end as shown in Figure 2 and the turned up ends of the fork engage the back of the plate 9 at a suitable position.
  • the polarity of the magnets is such that they tend to repel one another so that no return spring is necessary.
  • Movement of the end 15 of the lever 14 towards the support member 1 may be elfected in any suitable manner as for example by a Bowden cable so that the focus control can be brought to a convenient point of the receiver cabinet.
  • each pin also forms a fulcrum for an arcuate lever as 20, which carries at its remote end an operating pin 21 engaging the wall of a hexagonal aperture in the plate 19.
  • Each lever 20 carries a pad 22 for example of felt or rubber for engaging the neck of the tube.
  • the plate 19 is urged in the direction to cause closure of the pads on the neck of the tube by a spring 23 secured at one end to the plate 19 and at the other end to the support member 1.
  • a mandrel is employed. This, at one end has the same diameter as the neck of the tube and a portion of larger diameter on which the annular magnets are located.
  • the assembly is carried out by inserting the mandrel through the plate 4, the magnet 6, the magnet 7, plate 9 and main support member 1 in that order and locating the end of the mandrel in the locating device by manually turning the plate 19 to expand the levers 20, and allowing it to spring back.
  • the mandrel is thus located at one end by the locating device and at the other end it is located in the aperture in the plate 4.
  • the magnets are then positioned by the mandrel in their correct co-axial relationship with the mandrel and the securing tabs 5 and 8 are bent up to lock the magnets in position.
  • the mandrel can then be removed and the assembly is completed.
  • any variations in the outside diameter or thickness of the magnets are compensated and when magnet 7 is moved relatively to magnet 6 it remains co-axially aligned therewith and with the longitudinal axis of the cathode ray tube.
  • a permanent magnet focussing device for cathode ray tubes and the like comprising a main support member having an aperture adapted to accommodate the neck of the cathode ray tube, a first annular permanent magnet mounted within said main support and coaxially with said aperture, a secondary support member slideably mounted on said main support, a second annular permanent magnet Patented Mar. 27, 1956 mounted on said secondary support and slideable therewith, said second magnet being parallel to, coaxial with, and spaced from said first magnet, and a lever member pivotably mounted on said main support and coupled to said second permanent magnet, whereby motion of said lever changes the spacing between said two permanent magnets and thus the focussing action of the device.
  • both support members are each provided with apertured plates having peripheral tabs embracing and securing thereto their respective magnets.
  • a permanent magnet focussing device for cathode ray tubes and the like comprising a main support member having an aperture adapted to accommodate the neck of the cathode ray tube, a first annular permanent magnet fixedly mounted within said main support and coaxially with said aperture, a secondary support member slideably mounted on said main support, a second annular permanent magnet fixedly mounted on said secondary support and moveable therewith, said second magnet being parallel to, coaxial with, and spaced from said first magnet, both of said magnets being magnetized in the direction of their thickness and exhibiting opposite polarities such that they repel each other, a lever member pivotably mounted on said main support and having an end in engagement with the rear of said secondary support whereby motion of the other end of said lever changes the spacing between the two magnets, and an adjustable locating device mounted on said main support for securing the latter to the neck of the cathode ray tube, said locating device comprising a plurality of pins, a partially rotatable plate having a hexagonal aperture aligned with the aperture

Landscapes

  • Video Image Reproduction Devices For Color Tv Systems (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
US375782A 1952-08-26 1953-08-21 Permanent magnet focussing device for cathode ray tubes Expired - Lifetime US2740064A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB21490/52A GB763586A (en) 1952-08-26 1952-08-26 Improvements in or relating to permanent magnet focussing arrangements for cathode ray tubes

Publications (1)

Publication Number Publication Date
US2740064A true US2740064A (en) 1956-03-27

Family

ID=10163820

Family Applications (1)

Application Number Title Priority Date Filing Date
US375782A Expired - Lifetime US2740064A (en) 1952-08-26 1953-08-21 Permanent magnet focussing device for cathode ray tubes

Country Status (5)

Country Link
US (1) US2740064A (enrdf_load_stackoverflow)
BE (1) BE522315A (enrdf_load_stackoverflow)
DE (1) DE972501C (enrdf_load_stackoverflow)
FR (1) FR1090512A (enrdf_load_stackoverflow)
GB (1) GB763586A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2788468A (en) * 1954-08-04 1957-04-09 Marconi Wireless Telegraph Co Cathode ray tubes
US2820917A (en) * 1954-02-23 1958-01-21 Sprague Electric Co Focussing device
US2873413A (en) * 1954-12-04 1959-02-10 Philips Corp Magnetic-field-producing device
US2985788A (en) * 1956-01-19 1961-05-23 Westinghouse Electric Corp Spark gap device
US3098942A (en) * 1955-02-24 1963-07-23 Zenith Radio Corp Magnetic centering device for cathode ray tubes

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2418487A (en) * 1944-03-31 1947-04-08 Bell Telephone Labor Inc Cathode ray magnetic focusing device
US2443973A (en) * 1945-01-05 1948-06-22 Avco Mfg Corp Control device for cathode-ray focusing coils
US2569327A (en) * 1948-08-31 1951-09-25 Rca Corp Electron beam bender
US2580606A (en) * 1951-03-21 1952-01-01 Best Mfg Company Inc Cathode-ray tube focusing device
US2591820A (en) * 1948-02-07 1952-04-08 Pye Ltd Suspension mounting for the focussing device of cathode-ray tubes

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB670021A (en) * 1949-02-18 1952-04-09 Patrick Richard James Court Improvements in beam centering devices for cathode ray tubes

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2418487A (en) * 1944-03-31 1947-04-08 Bell Telephone Labor Inc Cathode ray magnetic focusing device
US2443973A (en) * 1945-01-05 1948-06-22 Avco Mfg Corp Control device for cathode-ray focusing coils
US2591820A (en) * 1948-02-07 1952-04-08 Pye Ltd Suspension mounting for the focussing device of cathode-ray tubes
US2569327A (en) * 1948-08-31 1951-09-25 Rca Corp Electron beam bender
US2580606A (en) * 1951-03-21 1952-01-01 Best Mfg Company Inc Cathode-ray tube focusing device

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2820917A (en) * 1954-02-23 1958-01-21 Sprague Electric Co Focussing device
US2788468A (en) * 1954-08-04 1957-04-09 Marconi Wireless Telegraph Co Cathode ray tubes
US2873413A (en) * 1954-12-04 1959-02-10 Philips Corp Magnetic-field-producing device
US3098942A (en) * 1955-02-24 1963-07-23 Zenith Radio Corp Magnetic centering device for cathode ray tubes
US2985788A (en) * 1956-01-19 1961-05-23 Westinghouse Electric Corp Spark gap device

Also Published As

Publication number Publication date
DE972501C (de) 1959-08-20
FR1090512A (fr) 1955-03-31
BE522315A (enrdf_load_stackoverflow)
GB763586A (en) 1956-12-12

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