GB2081418A - Spring for supporting shadow mask - Google Patents

Spring for supporting shadow mask Download PDF

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Publication number
GB2081418A
GB2081418A GB8122141A GB8122141A GB2081418A GB 2081418 A GB2081418 A GB 2081418A GB 8122141 A GB8122141 A GB 8122141A GB 8122141 A GB8122141 A GB 8122141A GB 2081418 A GB2081418 A GB 2081418A
Authority
GB
United Kingdom
Prior art keywords
shadow mask
spring
mask
fixing portion
supporting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB8122141A
Other versions
GB2081418B (en
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.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
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 Hitachi Ltd filed Critical Hitachi Ltd
Publication of GB2081418A publication Critical patent/GB2081418A/en
Application granted granted Critical
Publication of GB2081418B publication Critical patent/GB2081418B/en
Expired legal-status Critical Current

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Classifications

    • 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
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/06—Screens for shielding; Masks interposed in the electron stream
    • H01J29/07—Shadow masks for colour television tubes
    • H01J29/073—Mounting arrangements associated with shadow masks
    • 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
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F1/00—Springs
    • F16F1/02—Springs made of steel or other material having low internal friction; Wound, torsion, leaf, cup, ring or the like springs, the material of the spring not being relevant
    • F16F1/025—Springs made of steel or other material having low internal friction; Wound, torsion, leaf, cup, ring or the like springs, the material of the spring not being relevant characterised by having a particular shape

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)

Abstract

In a spring (3, 13) for supporting a shadow mask of a color picture tube including a mask fixing portion (4, 14) fixed to the shadow mask, a tilting portion (5, 15) contiguous with the mask fixing portion, and a panel pin attaching portion (6, 16) formed with an aperture (7, 17) for receiving therein a panel pin (9), the mask fixing portion (4, 14) is formed on its panel pin attaching portion side to be of a closed construction in which it is closed by a connection (14c) integral with the mask fixing portion or by a connection (22) separate from the mask fixing portion, to thereby prevent a reduction in the spring force of the spring for supporting the shadow mask which might otherwise be caused to occur by the deformation which the spring undergoes when fixed to the shadow mask. <IMAGE>

Description

SPECIFICATION Spring for supporting shadow mask Background of the invention This invention relates to a spring for supporting a shadow mask for securing the shadow mask of a color picture tube of the shadow mask type to the inner surface of a panel.
Generally the shadow mask structure of a color picture tube comprises a shadow mask, a frame secure to the periphery of the shadow mask for reinforcing same, and shadow mask support springs welded to the shadow mask and/or the frame.
The shadow mask support springs each generally include a mask fixing portion welded to a shirt of the shadow mask and/or the frame, a tilting portion contiguous with the mask fixing portion, and a panel pin attaching portion contiguous with the tilting portion and formed with an aperture for receiving therein a panel pin secured to the panel of the color picture tube.
The shadow mask supporting springs of this construction have the following functions: 1. In supporting a shadow mask on the panel, the springs support the shadow mask with a precision of 1/100 mm with respect to the positional relation between the shadow mask and the phosphor screen on the panel.
2. In the process for producing a color picture tube, it is necessary to attach and detach a shadow mask several times. To this end, shadow mask support springs are constructed to be readily attachable to the panel and detachable therefrom through panel pins. It is important that the fixed relative positions of the shadow mask and the phosphor screen on the panel be maintained at all times as designed.
3. While in operation, the shadow mask of a color picture tube is heated by the electron beam impinging thereon and expanded by the heat. This tends to cause a variation to occur in the positional relation between the shadow mask and the phos phorscreen of the panel, resulting in a reduction in colorimetric purity. The shadow mask support springs have the function of compensating for possible variations in the positional relation between the shadow mask and the phosphor screen on the panel.
As described hereinabove, the shadow mask support springs play an important role to enable color picture tube to achieve the desired results.
The shadow mask support springs are generally formed of stainless steel spring material of a thickness in the range between 0.25 and 0.3 mm. The springs of the prior art formed of this type of spring material in a unitary structure by means of a press are each formed with an opening on the panel pin attaching side of the mask fixing portion.
When the shadow mask support spring is attached to the shadow mask and/or the frame, the shadow mask support spring is positioned by means of a jig in a condition simulating the condition in which the components of the shadow mask structure are assembled on the panel. That is, the mask fixing portion is welded to the shadow mask skirt and/or the frame while a force is being exerted on the spring to keep same in a loaded condition. When welding is carried out, the mask fixing portion is deformed in positions adjacent the opening by the spring loading force. Thus the mask fixing portion is not restored to its original form upon removing the force exerted on the spring, so that it is only the spring force stemming from residual stress as subsequently to be described that is obtained.
Shadow mask support springs of the prior art have suffered the disadvantages due to the aforesaid preloading of the spring that the shadow mask becomes displaced and that the shadow mask structure is dislodged from the pins due to vibration and shock, because satisfactory support is unobtainable for the shadow mask.
Summary of the invention This invention has been developed for the purpose of obviating the aforesaid disadvantages of the prior art. Accordingly the invention has as its object the provision of a spring for supporting a shadow mask involving no reduction in spring force.
According to the invention, there is provided a spring for supporting a shadow mask comprising a mask fixing portion for securing the spring to the shadow mask, a tilting portion contiguous with the mask fixing portion, and a panel pin attaching portion contiguous with the tilting portion and formed with an aperture for receiving therein a panel pin, wherein the mask fixing portion is of a closed construction in which the panel pin attaching portion side thereof is closed by a connection.
According to the invention, the connection of the mask fixing portion of a spring for supporting a shadow mask of the aforesaid contruction is formed integrally with the mask fixing portion.
According to the invention, the connection of the mask fixing portion of a spring for supporting a shadow mask of the aforesaid construction comprises a separate member secured to the mask fixing portion.
According to the invention, the connection of the mask fixing portion of a spring for supporting a shadow mask of the aforesaid construction comprises a separate member formed in manner to cover the entire mask fixing portion.
By way of example only certain illustrative embodiments of the invention will now be described with reference to the accompanying drawings.
Brief description of the drawings Figure 1 is a perspective view showing the manner in which a shadow mask of a color picture tube is attached to a panel; Figure 2A is a schematic front view of a spring for supporting a shadow mask of the prior art; Figure 2B is a sectional view taken along the line liB-IIB in Figure 2A; Figure 3 is a schematic front view of the spring for supporting a shadow mask comprising one embodiment of the invention; Figure 4 is a schematic front view of another embodiment of the invention; Figure 5A is a schematic front view of a modification of the embodiment shown in Figure 4; and Figure 5B is a sectional view taken along the line VB-VB in Figure 5A.
Description of the preferred embodiments Figure 1 shows the relation between a shadow mask structure and a panel in a color picture tube. A shadow mask 1 has a reinforcing frame 2 secured to its periphery. The numeral 3 designates a spring for supporting the shadow mask 1 welded to the shadow mask 1 and the frame 2. The shadow mask structure comprising the shadow mask 1, the reinforcing frame 2 and the spring 3 is attached to a panel 8 of the color picture tube by inserting a pin 9 fixed to the inner surface of the panel 8 in an aperture 7 formed in each spring, to keep the phosphor screen, not shown, on the panel 8 and the shadow mask 1 in a predetermined positional relation.
The spring 3 for supporting a shadow mask of the prior art shown in Figures 2A and 2B is formed of stainless steel spring material of a thickness in the range between 0.25 and 0.3 mm as a unitary structure by means of a press. The spring 3 comprises a mask fixing portion 4welded to a shadow mask skirt and/or the frame as indicated by x, a tilting portion 5 contiguous with the mask fixing portion 4, and a panel pin attaching portion 6 contiguous with the tilting portion 5, the panel pin attaching portion 6 being formed with an aperture 7 for receiving therein a panel pin.
There are two assembly methods available for assembling a shadow mask structure. One assembly method which is a two step method consists in welding the shadow mask support spring to the frame and welding a shadow mask to the frame, and the other assembly method which is a one step method consists in simultaneously welding the frame, spring and shadow mask together. Whichever method may be used, all the parts are relatively positioned by means of jigs in a condition simulating the condition in which they are assembled on the panel, so that when each spring for supporting the shadow mask is welded to the frame and/or the shadow mask skirt welding is carried out in a condition in which a force is exerted on the spring.
Thus the spring is preloaded when welding is effected. At this time, prior to welding, a section 4a of the mask fixing portion 4 adjacent the base of the tilting portion 5 of the spring 3 is subjected to torsion and the tilting portion 5 is subjected to deflection, and a force tending to resist the torsion and deflection acts as a spring force. The deflection to which the tilting portion 5 is subjected is very small in amount, and the torsion to which the section 4a of the mask fixing portion 4 is subjected accounts for the majority of the spring force exerted by the spring 3.As a result of the torsion to which the section 4a is subjected, the spring 3 undergoes deformation in such a manner that welded sections 4b with spot welds x on opposite sides of the opening are displaced outwardly as indicated by broken lines as shown in Figures 2A, and an upper end 4c of the mask fixing portion 4 is bent in a direction away from the shadow mask 1 as indicated by broken lines in Figure 2B. When the spring 3 is welded to the frame and/or the shadow mask skirt, the spring 3 is deformed as aforesaid. Thus the spring 3 is not restored to its original condition even if the force exerted thereon is removed, so that it is only the spring force attributed to residual stress that is obtained. Stated differently, the spring force of the spring 3 is much lowerthan would be the case when welding is carried out in a condition in which no torsion is applied.As a result, satisfactory support is unobtainable for the shadow mask and such troubles as displacements of the shadow mask and dislodging of the shadow mask structure from the panel pins due to vibration or impact would be inevitable.
The present invention avoids a reduction in the spring force of the shadow mask support springs by providing the featurethatthe mask fixing portion is of a closed construction in which the panel pin attaching portion side thereof is closed by a connection.
Figure 3 shows one embodiment in which a shadow mask support spring 13 is composed of two spring parts 13A and 13B, one spring part 13A being substantially rectangular in shape and including a mskfixing portion 14 and a tilting portion 15 disposed substantially in the central portion of the mask fixing portion 14 which is formed by raising and bending the material of the mask fixing portion 14 and the other spring part 13B including a panel pin attaching portion 16 formed with an aperture 17 for inserting a panel pin and a fixing portion 20 extending along the tilting portion 15 and welded thereto.
As aforesaid, in the shadow mask support pin 13, the mask fixing portion 14 is of a closed construction in which it is closed by a connection 14c on the side of the panel pin attaching portion 16. By virtue of this construction, outward displacement of welding sections 14b which might otherwise be caused to occur by torsion to which an upper section 14a of the mask fixing portion 14 adjacent the base of the tilting portion 15 might be subjected when the spring 13 is welded to the frame can be avoided, thereby making it possible to prevent a reduction in the spring force ofthespring 13.
Figure 4 shows another embodiment in which a connecting plate 21 is welded to the mask fixing portion 4 of the shadow mask support spring 3 of the prior art shown in Figure 2A. More specifically, the connecting plate 21 is secured to the mask fixing portion 4 on the side of the panel pin attaching portion 6 to give a closed construction to the mask fixing portion 4. By constructing the shadow mask support spring as aforesaid according to the invention, the same results as obtained by the embodiment shown in Figure 3 can be achieved. The embodiment shown in Figure 4 is more advantageous than that shown in Figure 3 in that higher dimensional precision of the tilting portion and the panel pin attaching portion of the spring is more readily obtainable.
Figures 5A and 5B show a modification of the embodiment shown in Figure 4, in which the con necting plate 21 of the embodiment shown in Figure 4 is replaced by a connecting plate 22 of a size large enough to cover the mask fixing portion 4 in its entirety. The connecting plate 22 is substantially rectangular in shape and has a closed construction, with a window 23 being formed substantially in the central portion thereof for permitting the tilting portion 5 and panel pin attaching portion 6 to extend therethrough. The connecting plate 22 is welded to the mask fixing portion 4 in positions indicated byx.
Circular apertures 24 formed in the connecting plate 22 in positions each adjacent one of the positions indicated by x are used for joining the mask fixing portion 4 to the frame and/or the shadow mask skirt by spot welding.
Modification shown in Figures 5A and 5B can achieve an additional effect besides the effects achieved by the embodiment shown in Figure 4.
More specifically, by virtue of the facts that the spring undergoes less torsion and that the mask fixing portion 4 is joined by spot welding to the connecting plate 22 only in positions indicated by x, the vibration of the speaker, etc., transmitted to the shadow mask from the panel is damped between the mask fixing portion and the connecting plate 22 of the shadow mask support springs, to thereby avoid a reduction in colorimetric purity that might otherwise be caused by the vibration of the shadow mask.

Claims (5)

1. A spring for supporting a shadow mask comprising: a mask fixing portion for securing the spring to the shadow mask; a tilting portion contiguous with the mask fixing portion; and a panel pin attaching portion contiguous with the tilting portion and formed with an aperture for receiving therein a panel pin; wherein the mask fixing portion is of a closed construction in which the panel pin attaching portion side thereof is closed by a connection.
2. A spring for supporting a shadow mask as claimed in claim 1, wherein the connection of the mask fixing portion is formed integrally with the mask fixing portion.
3. A spring for supporting a shadow mask as claimed in claim 1, wherein the connection of the mask fixing portion comprises a separate member secured to the mask fixing portion.
4. A spring for supporting a shadow mask as claimed in claim 3, wherein the connection in the form of a separate member is formed in a manner to cover the entire mask fixing portion.
5. A spring for supporting a shadow mask, substantially as hereinbefore described with reference to and as shown by Figures 3 to 5 of the accompanying drawings.
GB8122141A 1980-07-23 1981-07-17 Spring for supporting shadow mask Expired GB2081418B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1980103249U JPS5727658U (en) 1980-07-23 1980-07-23

Publications (2)

Publication Number Publication Date
GB2081418A true GB2081418A (en) 1982-02-17
GB2081418B GB2081418B (en) 1984-07-25

Family

ID=14349164

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8122141A Expired GB2081418B (en) 1980-07-23 1981-07-17 Spring for supporting shadow mask

Country Status (3)

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JP (1) JPS5727658U (en)
KR (1) KR850002500Y1 (en)
GB (1) GB2081418B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2258941A (en) * 1991-08-21 1993-02-24 Samsung Electronic Devices Mounting shadow mask in crt.

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2258941A (en) * 1991-08-21 1993-02-24 Samsung Electronic Devices Mounting shadow mask in crt.
US5289080A (en) * 1991-08-21 1994-02-22 Samsung Electron Devices Co., Ltd. Mask frame damper for color cathode ray tubes
GB2258941B (en) * 1991-08-21 1995-11-08 Samsung Electronic Devices Mask mounting for colour cathode ray tubes

Also Published As

Publication number Publication date
KR850002500Y1 (en) 1985-10-19
KR830001045U (en) 1983-09-22
GB2081418B (en) 1984-07-25
JPS5727658U (en) 1982-02-13

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19950717