ISO-3820-1978.pdf

《ISO-3820-1978.pdf》由会员分享，可在线阅读，更多相关《ISO-3820-1978.pdf（12页珍藏版）》请在三一文库上搜索。

1、Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 23:18:31 MDTNo reproduction or networking permitted without license from IHS -,-,- Copyright International Organization for Standa

2、rdization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 23:18:31 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 38204978 (E) Cinematography - Sprockets for 8 mm Type motion-pictur

3、e film - Dimensions and design 1 SCOPE AND FIELD OFAPPLICATION This International Standard lays down the dimensions and specifies requirements for the design of sprockets used with 8 mm Type S motion-picture raw stock or processed film. 2 REFERENCE ISO 1700, Cinema tograph y - 8 mm Type Smotion-pict

4、ure raw stock film - Cu tting and perfora ting dimensions. 3 DIMENSIONS AND CHARACTERISTICS 3.1 The teeth shall be equally spaced at an index angle of 360/N degrees, where N is the number of teeth. A suitable tolerante for the index angle is * 1 minute of arc for sprockets having 12 to 24 teeth and

5、+ 30 seconds of arc for sprockets having 25 to 84 teeth. 3.2 The root diameter D is computed from the equation : P D=Nx-T 77 where P is the Perforation pitch; N is the number of teeth; T is the film thickness. The root diameters in table 1 B were derived using a value for T of 0,15 mm (0.006 in). If

6、 Optimum working condi- tions are desired with film materials of other thicknesses, table 1 B should be recomputed. 3.3 The minimum value of R, as depicted in figure 1, has been Chosen as 3,96 mm (0.156 in). This is an arbitrary choice, but seems appropriate for 8 mm equipment. The shape of the film

7、 path as the film leaves the root of the Sprocket tooth is determined by film stiffness, set, and tension, as well as by the shape and location of rollers or guides. For the specified tooth shape, the film has been allowed to Slip back over the root circle a distance of 0,046 mm (0.001 8 in) measure

8、d at the pitch line film thickness assumed to be 0,15 mm (0.006 in), by the time the contact Point between film and tooth has reached the assumed working height, H, of 0,66 mm (0.026 in) (measured radially from the root circle). This analysis applies to the feed Sprocket, for which the Sprocket pitc

9、h is generally greater than the Perforation pitch, and the film must Slip in the direction opposite to the direction of motion. The direction of the friction forte between the film and root surface is such as to assist the feed or the driving action. Of the total 0,046 mm (0.001 8 in) accommodation

10、provided at each tooth for film Slippage, approximately 0,013 mm (0.000 5 in) is allocated to the combined tolerante of Perforation pitch and Sprocket tooth pitch (shorter than average Perforation pitch combined with longer than average tooth pitch). An additional 0,008 mm (0.003 in) is allocated fo

11、r, and corresponds approximately to, the distortion resulting from 0,58 N (56,7 gf) of contact Ioading. The remaining 0,25 mm (0.001 0 in) corresponds to 0,6 % of film shrinkage. lt should be noted that a combina- tion of 1,16 N (113,4 gf) of load and approximately 0,4 % shrinkage with pitch toleran

12、tes is about equivalent. By this procedure the values of X, are determined. As shown in figure 3, X, is the distance measured perpendicular to the radial line intersecting the root of the tooth from a Point on the tooth which is 0,66 mm (0.026 in) above the root circle. 3.4 The minimum values of R,

13、(see figure 1) have been computed for the same X, and the same accommodation of 0,046 mm (0.001 8 in) assuming a displacement function proportional to the Square of time (see annex, reference 2). These values of , are set out in tables 1A and 1 B. For the exit film paths corresponding to larger valu

14、es of , or , including a straight tangent path, the accommodation sf 0,046 mm (0.001 8 in) for film Slippage takes place in less than 0,66 mm (0.026 in) of the working height (or more accommodation results at the same height). The accom- modation takes place more slowly for the exit path defined by

15、minimum values of ,; therefore, these are recom- mended where maximum uniformity of motion is desired. 3.5 The desired tooth shape tan be generated by a hob corresponding to the basic rack specified by K, and B, as tabulated (see table 3 and figure 4). If the first hob covers the range of N from 12

16、to 24, inclusively, and the second hob covers the range of N from 25 to 84, inclusively, no deviations in tooth shape from the ideal greater than 0,003 05 mm (0.000 12 in) will occur. 3.6 The tooth width at the base, dimension W, allows ample material for rounding off the tip while preserving the 0,

17、66 mm (0.026 in) working height. In some instances some additional height is available. The value Chosen does not limit the angle of wrap on the Sprocket as a wider tooth 1 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standar

18、ds 1/9972545001 Not for Resale, 04/23/2007 23:18:31 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 38204978 (E) would. If the wrap length is defined as one-half of the sum of the number of pitch lengths in the arc of engagement, E, and the number of pitch lengths in th

19、e arc of contact, C (figure 1), then the wrap length may be as high as 9 IM pitch lengths without producing interference at the entering teeth of a drive Sprocket if the film shrinkage does not exceed 0,8 %. 3.7 The lateral Profile of the Sprocket has been derived on the assumption that the film is

20、channel-guided at or near the Sprocket. This guiding may be provided by fixed guides, by the flanges of an adjacent roller at the entering Position, or preferably by flanges on the Sprocket itself. When a fixed guide is needed at the perforated edge and the film is urged against the guide by a sprin

21、g or other means, the lateral dimensions L of the tooth tan be increased. If the Sprocket teeth are to perform the function of side guiding, then their lateral dimension L may be increased to 0,902 0 oi 3 mm (0.035 5 _ _ I E . 000 5 in) with special consideration given to tooth alignment, smooth- ne

22、ss of the sides, and rounding or tapering at the tips. When the Sprocket teeth have been increased in width to perform the function of lateral guiding, the , value, for the radius of the corners of the Sprocket tooth, should be increased to comply with the radius of the Perforation fillet, nominally

23、 0,13 mm (0.005 in). 3.8 In Order for the film guides to function properly, the Sprocket eccentricity as mounted in Operation should not exceed 0,025 mm (0.001 0 in) and the lateral weave or wobble measured at the root circle should not exceed 0,025 mm (0.001 0 in). Less eccentricity may be required

24、 for a special application such as a Sound Printer Sprocket. 3.9 In some cases of large-scale layouts or critical com- parisons, it may be more convenient to work with values of X, than values of B. NOTE - The inch dimensions in this International Standard have been converted from the specified metr

25、ic dimensions, but have not been carried out to two more places as specified in ISO 370. They do, however, reflect the engineering practice in the countries using the Imperial System of units. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NA

26、SA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 23:18:31 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 38204978 (E) TAB LE 1 A - Sprocket dimensions, in millimetres N Dd Dc Dh K B 2 XT 12 16,021 15,971 15,895 1,520 0,047 12,584 0,246 0 13 17,363 17,316

27、17,232 1,574 0,057 13,381 0,240 8 14 18,716 18,658 18,569 1,625 0,067 14,184 0,236 3 15 20,064 20,002 19,906 1,674 0,078 14,988 0,232 4 16 21,412 21,345 21,244 1,722 0,087 15,803 0,228 9 17 22,759 22,689 22,581 1,768 0,097 16,619 0,225 8 18 24,107 24,033 23,918 1,813 0,106 17,431 0,223 1 19 25,455 2

28、5,376 25,255 1,856 0,116 18,253 0,220 6 20 26,802. 26,720 26,592 1,899 0,124 19,082 0,218 3 21 28,150 28,063 27,930 1,940 0,133 19,903 0,216 3 22 29,498 29,407 29,267 1,981 0,142 20,735 0,214 4 23 30,846 30,750 30,604 2,020 0,151 21,564 0,212 7 24 32,193 32,084 31,941 2,059 0,159 22,400 0,211 1 26 3

29、4,889 34,781 34,616 2,135 0,176 24,072 0,208 3 28 37,584 37,468 37,290 2,208 0,192 25,763 0,205 8 30 40,280 40,156 39,965 2,280 0,208 27,453 0,203 7 32 42,975 42,843 42,639 2,349 0,224 29,159 0,201 8 34 45,67 1 45,530 45,313 2,417 0,239 30,862 0,200 2 36 48,366 48,217 47,988 2,483 0,254 32,585 0,198

30、 7 38 5 1,062 50,904 50,662 2,549 0,269 34,326 0,197 3 40 53,757 53,59 1 53,337 2,613 0,283 36,065 0,196 1 42 56,452 56,279 56,011 2,675 0,298 37,798 0,195 1 44 59,148 58,966 58,686 2,737 0,312 39,557 0,194 1 46 6 1,843 6 1,653 6 1,360 2,798 0,326 41,341 0,193 1 48 64,539 64,340 64,035 2,858 0,340 4

31、3,112 0,192 2 50 67,234 67,027 66,709 2,918 0,353 44,905 0,191 5 52 69,930 69,714 69,383 2,976 0,367 46,700 0,190 8 54 72,625 72,402 72,058 3,033 0,381 48,494 0,190 2 56 75,321 75,089 74,732 3,091 0,394 50,330 0,189 4 60 80,711 80,463 80,081 3,204 0,420 53,993 0,188 4 64 86,102 85,838 85,430 3,314 0

32、,446 57,707 0,187 4 68 9 1,493 91,212 90,779 3,422 0,471 61,439 0,186 6 72 96,884 96,586 96,128 3,528 0,496 65,24 1 0,185 8 76 102,275 101,961 101,477 3,633 0,521 69,08 1 0,185 1 80 107,666 107,335 106,826 3,735 0,545 72,955 0,184 5 84 113,057 112,709 112,174 3,837 0,569 76,895 0,183 9 1 N = Number

33、of teeth Dci = Root diameter, D Eno3 of drive Sprocket of 4,234 pitch Dc = Root diameter, D + zto3 of combination Sprocket of 4,221 pitch Dh 0 = Root diameter, D _ o o3 of hold-back Sprocket of 4,201 pitch I Film thickness = 0,152. For other thicknesses : pitch Root diameter = N X- thickness 7r K =

34、Circular arc radius for tooth shape, _ E o5 , 6 = Radial distance of arc centre inside root circle, 0” R2 = Minimum radius of film path concave to Sprocket XT = Offset of tooth at working height Tooth working height, H = 0,660 Maximum pitch differente = 0,046 Minimum film path radius convex to Sproc

35、ket, R, = 3,962 Numerital values in millimetres. 3 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 23:18:31 MDTNo reproduction or networking permitted without license from IHS -,

36、-,- ISO38204978(E) TABLE 1 B - Sprocket dimensions, in inches N Oci Oc h K B * XT 12 0.630 7 0.628 8 0.625 8 0.059 8 0.001 9 0.495 4 0.009 69 13 0.683 8 0.681 7 0.678 4 0.062 0 0.002 2 0.526 8 0.009 48 14 0.736 9 0.734 6 0.731 1 0.064 0 0.002 6 0.558 4 0.009 30 15 0.789 9 0.787 5 0.783 7 0.065 9 0.0

37、03 1 0.590 1 0.009 15 16 0.843 0 0.840 4 0.836 4 0.067 8 0.003 4 0.622 2 0.009 01 17 0.896 0 0.893 3 0.889 0 0.069 6 0.003 8 0.654 3 0.008 89 18 0.949 1 0.946 2 0.941 7 0.071 4 0.004 2 0.686 3 0.008 78 19 1.002 2 0.999 1 0.994 3 0.073 1 0.004 6 0.718 6 0.008 69 20 1.055 2 1.052 0 1.046 9 0.074 8 0.0

38、04 9 0.751 3 0.008 59 21 1.108 3 1.1048 1.099 6 0.076 4 0.005 2 0.783 6 0.008 52 22 1.161 3 1.157 8 1.152 2 0.078 0 0.005 6 0.816 3 0.008 44 23 1.2144 1.210 6 1.204 9 0.079 5 0.005 9 0.849 0 0.008 37 24 1.267 4 1.263 5 1.257 5 0.081 1 0.006 3 0.881 9 0.008 31 26 * 1.373 6 1.369 3 1.362 8 0.084 1 0.0

39、06 9 0.947 7 0.008 20 28 1.479 7 1.475 1 1.468 1 0.086 9 0.007 6 1.014 3 0.008 10 30 1.585 8 1.580 9 1.573 4 0.089 8 0.008 2 1.080 8 0.008 02 32 1.691 9 1.686 7 1.678 7 0.092 5 0.008 8 1.148 0 0.007 94 34 1.798 1 1.792 5 1.784 0 0.095 2 0.009 4 1.2150 0.007 88 36 1.904 2 1.898 3 1.889 3 0.097 8 0.01

40、0 0 1.282 9 0.007 82 38 2.010 3 2.004 1 1.994 6 0.100 4 0.010 6 1.351 4 0.007 77 40 2.116 4 2.109 9 2.099 9 0.102 9 0.011 1 1.4199 0.007 72 42 2.222 5 2.215 7 2.205 2 0.105 3 0.011 7 1.488 1 0.007 68 44 2.328 7 2.321 5 2.310 5 0.107 8 0.012 3 1.557 4 0.007 64 46 2.434 8 2.427 3 2.415 7 0.110 2 0.012

41、 8 1.627 6 0.007 60 48 2.540 9 2.533 1 2.521 1 0.112 5 0.013 4 1.697 3 0.007 57 50 2.647 0 2.638 9 2.626 3 0.114 9 0.013 9 1.767 9 0.007 54 52 2.753 1 2.744 6 2.731 6 0.117 2 0.014 4 1.838 6 0.007 51 54 2.859 3 2.850 5 2.836 9 0.119 4 0.015 0 1.909 2 0.007 49 56 2.965 4 2.956 3 2.942 2 0.121 7 0.015

42、 5 1.981 5 0.007 46 60 3.177 6 3.167 8 3.152 8 0.126 1 0.016 5 2.125 7 0.007 42 64 3.389 8 3.379 4 3.363 4 0.130 5 0.017 6 2.271 9 0.007 38 68 3.602 1 3.591 0 3.574 0 0.134 7 0.018 5 2.418 9 0.007 35 72 3.814 3 3.802 6 3.784 6 0.138 9 0.019 5 2.568 5 0.007 31 76 4.026 6 4.014 2 3.995 2 0.143 0 0.020

43、 5 2.719 7 0.007 29 80 4.238 8 4.225 8 4.205 7 0.147 0 0.021 5 2.872 2 0.007 26 84 4.451 1 4.437 4 4.416 3 0.151 1 0.022 4 3.027 4 0.007 24 N = Number of teeth Dd = Root diameter, D aool of drive Sprocket of 0.166 7 pitch D, = Root diameter, D gmoo of combination Sprocket of 0.166 2 pitch Dh = Root

44、diameter, D 0 - 0.001 of hold-back Sprocket of 0.165 4 pitch Film thickness = 0.006 0. For other thicknesses : pitch Root diameter - N X- thickness 71 K 0 = circular arc radius for tooth shape, _ o oo2 . 5 = Radial distance of centre arc of inside root circle, i.“ 5 R, = Minimum radius of film path

45、concave to Sprocket XT = Offset of tooth at working height Tooth working height, H = 0.026 0 Maximum pitch differente = 0.001 8 Minimum film path radius convex to Sprocket, R, = 0.156 0 Numerital values in inches. Copyright International Organization for Standardization Provided by IHS under license

46、 with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 23:18:31 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 382001978(E) FIGURE 1 - Sprocket/f ilm relationship F IG UR E 2 - Sprocket drum Profile Section X-X Film F I GUR E 3 - Sprocket t

47、ooth side prof ile Q Irr 7” max. (Optional) TABLE 2 - Dimensions Dimension in A F max. G max. H K J L M Q max. Rl R2 R, max. R4 S W Y (where appl icable) 0 I 71 + wo 0 0 . 028 + 0.004 0 See tables 1A and 1 B See 3.6 See tables 1A and 1 B See 3.6 0,lO 0.004 0,18 0.007 0,66 0.026 See tables 1 A and 1

48、B 8 08 + 0,03 0 318 + 0.001 I 0 . 0 0,61 + 0,03 0.024 + 0.001 6,58 k 0,05 0.259 If: 0.002 0,15 0.006 See 3.3 See tables 1A and 1 B 0,08 0.003 0,13 $r 0,05 0.005 + 0.002 0,71 f 0,03 0.028 + 0.001 0 71 + 0,05 0 028 + 0.002 I 0 . 0 Provide clearance 5 Copyright International Organization for Standardiz

49、ation Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 23:18:31 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 38204978 (E) Dimensions in millimetres (Inch values in parentheses) / L See note 2 FIGURE 4 - Basic