| 摘要 |
1,268,028. Making shadow masks; stamping. NORTHERN METAL PRODUCTS Inc. 25 June, 1970 [15 July, 1969], No. 30783/70. Headings B3A and B3Q. A method of forming a colour television uniframe shadow mask, Fig. 2, from a deep drawn shadow mask having a central foraminous portion 10 and wall portions comprises the steps of supporting the drawn down mask over substantially all of its concave surface with a first set of dies 32, 34 and 36, holding the foraminous portion 10, and bending the wall portions into flanged 16, and ribbed 18, supporting members by moving a second set of dies 26 and 28. An air cylinder retracts the plug 36 and a second air cylinder 62 rotates a cam 54 having spiral grooves. Slides 30, carrying dies 32 and 34, each have a follower pin 70 which passes through a slot 72 and rides in one of the spiral grooves so that when cam 54 is rotated by cylinder 62 the dies 32 and 34 are moved radially inward into the space left vacant by plug 36. The deep drawn shadow mask is then lowered over dies 32 and 34 and the above described sequence of steps reversed so that dies 32 and 34 move to their minimum radial position and are locked by the plug 36. The foraminous portion 10 is clamped to the top of dies 32 and 34 and plug 36 and hydraulic cylinders 40 move the external dies 28 inwards to press ribs 18 into the side walls and simultaneously fold under the side walls to form flange 16. External dies 26 are then moved inwardly by hydraulic cylinders 41 to emboss corner ribs and to tuck under the corners. |
