| 摘要 |
1,267,385. Cutting apparatus. ZUHLKE & BRANDLI A.G. 24 July, 1969 [5 Nov., 1968], No. 37301/69. Heading B5A. Blanks are separated from a thermoplastic sheet by tensioning the sheet, weakening it in a zone along the outline of the desired blank and then separating the part i.e. the blank within the weakened zone from the sheet. In Fig. 1 a light-reflecting web 40 is fed step by step by a motor 3 from a reel 2, and passes over a guide roller 8 and between intermittently driven rollers 9, 10, and is held under tension by a roller 6 on a pivoted lever 5 biased by a spring 7. Following a stepwise feeding of the web, a circular heated electrode 60, which determines the size and shape of the intended blank, is lowered and -forces the web against the top surface 66 and partially penetrates the web, Fig. 2. The blank, which is to form part of a dental mirror, is then separated from the web by the downward movement of a plunger 28 which carries a male part 52 of a mirror frame which forces the blank into a female part 51 located on a support 50. The plunger is carried by 'a yoke 22 'reciprocated by a motor 26 and crank mechanism 23-25 and guided vertically by posts 21. The electrode carrier 57 is received within an intermediate carrier 53 with the interposition of springs 58, and springs 55 are located between the carrier 53 and the yoke. The electrode '60 comprises an electric resistance heater. |
