1、BRITISH STANDARD BS 5550-3.10.2: 1980 Incorporating Amendment Nos. 1 and2 Cinematography Part 3: 35 mm film Section 3.10 Sprockets Subsection 3.10.2 Specification for universal sprockets for 35 mm perforated film.BS5550-3.10.2:1980 This British Standard, having been approved by the Cinematograph Sta
2、ndards Committee and endorsed by theChairman of the Engineering Divisional Council, was publishedunder the authority of the General Council on 29 November 1965 as BS 3946 BSI 02-2000 The following BSI references relate to the work on this standard: Committee references CMS/28 Draft for comment D64/3
3、213 ISBN 0 580 35813 5 Co-operating organizations The Cinematograph Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Association of Cinematograph, Televi
4、sion and Allied Technicians* Board of Trade British Broadcasting Corporation British Film Institute British Film Producers Association* British Kinematograph, Sound and Television Society* British Photographic Manufacturers Association* Cinematograph Exhibitors Association of Great Britain and Irela
5、nd* Federation of British Film Makers* Federation of Specialised Film Associations Home Office Illuminating Engineering Society Incorporated Association of Kinematograph Manufacturers Ltd.* Independent Television Companies Association Kinematograph Renters Society Ltd. Ministry of Defence, Army Depa
6、rtment* Royal Photographic Society The Government department and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committees entrusted with the preparation of this British Standard: British Gear Manufactu
7、rers Association Film Laboratory Association Milling Cutter and Reamer Association Royal Naval Film Corporation Scientific Instrument Manufacturers Association Manufacturers of cinematograph projectors, projector sprockets, and motion picture film Amendments issued since publication Amd. No. Date of
8、 issue Comments 6239 August 1967 2943 September 1980 Indicated by a sideline in the marginBS5550-3.10.2:1980 BSI 02-2000 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Dimensions 1 4 Angular pitch error of teeth 1 5 Parallelism of end diameters
9、1 6 Misalignment of teeth 1 7 Concentricity of intermittent sprockets 1 Figure 1 Misalignment of teeth 1 Figure 2 Universal sprockets for 35 mm perforated film with “broad” or “narrow” perforations 2 Table 1 Dimensions for 16-tooth, universal sprockets (feed, intermittent and hold-back) 3 Table 2 Di
10、mensions for 24-tooth universal sprockets (feed and hold-back) 4 Table 3 Dimensions for 32-tooth universal sprockets (feed and hold-back) 5BS5550-3.10.2:1980 ii BSI 02-2000 Foreword This standard makes reference to the following British Standard: BS 5550-3.1.1, Cutting and perforating dimensions of
11、35 mm motion-picture film and magnetic film. The British Standard for sprockets for 35 mm cinematograph projectors, BS1967, was first issued in 1953. It was revised in 1965 and is now renumbered BS 5550-3.10.1. It relates to sprockets for use with perforated film in accordance with Type P of BS 5550
12、-3.1.1. Over the years there has been an increasing use of35mm film with “narrow” perforations, Type AC, as specified in BS 5550-3.1.1, requiring the use of a sprocket with correspondingly narrower teeth. This British Standard, first issued in 1965 as BS3946 and confirmed in 1978, provides for such
13、a sprocket. As all British Standards on cinematography are eventually to become Sections or Subsections of BS5550, this standard has been renumbered as BS5550-3.10.2. Since this sprocket may be used not only with Type AC film (having a perforation 1.98 mm wide by 1.85 mm high) but also with Type P (
14、2.80mm by 1.98mm) and Type N (2.08 mm by 1.85 mm) of BS 5550-3.1.1, and with a film having a perforation 1.98 mm wide by 1.98 mm high, as used by some European countries, it is, for convenience, designated a “universal” sprocket, and BS 1967 (now BS 5550-3.10.1) has been retitled “Broad tooth sprock
15、ets for 35 mm perforated film”. It is recommended that, for future practice in cinematograph projectors and equipment, sprockets complying with this standard should be used and that, for motion-picture techniques, the use of sprockets complying with the requirements of BS 5550-3.10.1 should be disco
16、ntinued. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document c
17、omprises a front cover, an inside front cover, pages i and ii, pages1 to 5 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS5550-3.10.2:1980 BSI 02-2000 1 1 Scope
18、This British Standard relates to the dimensions of16-teeth intermittent sprockets, and 16-teeth, 24-teeth and 32-teeth feed and hold-back sprockets for35mm perforated film having perforations in accordance with Type P, N and AC of BS 5550-3.1.1. It specifies the essential dimensions for accurate eng
19、agement with the film, and gives recommended dimensions in respect of the form of the teeth. NOTEThe dimensions of sound-head sprockets are normally similar to those given in this standard for feed sprockets. 2 Definitions For the purposes of this British Standard the following definitions apply: 2.
20、1 sprocket a toothed drum for transporting film 2.2 feed sprocket a sprocket serving to draw the film in its direction of rotation; usually applied to a sprocket drawing film from a take-off 2.3 intermittent sprocket an intermittently rotating sprocket, to advance the film one frame at a time past t
21、he picture aperture at the designated rate 2.4 sound sprocket a constant-speed sprocket which feeds film past the scanning point in a sound head 2.5 hold-back sprocket a sprocket serving to restrain the film against tension; usually applied to a sprocket restraining the passage of the film to a take
22、-up spool 3 Dimensions The sprockets shall conform to the “standard” dimensions given in Table 1 to Table 3 inclusive, appropriate to the size and function of the sprocket, and shall comply with the requirements of Clauses4 to 7 inclusive. It is recommended that the sprockets should also conform to
23、the “recommended” dimensions inTable 1 toTable 3. NOTEIn view of the close similarity in the dimensions and appearance of feed sprockets and hold-back sprockets it is recommended that such sprockets should be permanently marked to indicate their use. 4 Angular pitch error of teeth The cumulative pit
24、ch error between any two teeth shall not exceed4 minutes of arc. 5 Parallelism of end diameters In any one sprocket the diameters D (Figure 2) of the two ends shall be equal within 0.0004 in (0.010 mm). 6 Misalignment of teeth The misalignment of the working faces of any pair of teeth (dimensionA, F
25、igure 1) shall not exceed the following amounts: 7 Concentricity of intermittent sprockets When an intermittent sprocket is rotated on a true mandrel, the total variation in a dial gauge reading taken on each of the cylindrical surfaces D (Figure 2) during one complete revolution of the sprocket sha
26、ll not exceed0.0002 in (0.005mm). Feed and hold-back sprockets 0.001 in (0.025 mm) Intermittent sprockets 0.0004 in (0.010 mm) Figure 1 Misalignment of teethBS5550-3.10.2:1980 2 BSI 02-2000 NOTE 1Apart from the essential dimensions, these figures are diagrammatic only, and are not intended to indica
27、te details of design. NOTE 2By reason of the usual methods of production it is not practicable to produce a tooth form with precisely sharp corners at the base of the tooth, and a radius up to0.002 in (0.05 mm) is not regarded as cause for rejection of the sprockets. If the nature of the equipment i
28、n which the sprocket is to be used is such that any radius, however small, at the base of the tooth is inadmissible, this should be stated by the purchaser in his original enquiry. Figure 2 Universal sprockets for 35 mm perforated film with “broad” or “narrow” perforationsBS5550-3.10.2:1980 BSI 02-2
29、000 3 Table 1 Dimensions for16-tooth, universal sprockets (feed, intermittent and hold-back) 1 2 3 4 5 Dimension Inches Approximate millimetre equivalents Angle A 1.124 0.001 28.55 0.025 B C 0.039 0.002 0.99 0.05 Feed Sprockets 0.950 0.001 24.13 0.025 Standard dimensions D Intermittent Sprockets 0.9
30、50 0.001 24.13 0.025 Hold-back sprockets 0.940 0.001 23.88 0.025 No part of the sprocket, other than the teeth shall be proud of the cylindrical surface of diameter D Feed Sprockets 22 30 1.5 ! Intermittent Sprockets 22 30 0.75 Hold-back Sprockets 22 30 1.5 R 0.077 1.96 S 0.004 0.10 “ 7 30 Feed Spro
31、ckets 0.940 0.002 23.88 0.05 T Intermittent Sprockets 0.940 0.002 23.88 0.05 Recommended dimensions Hold-back Sprockets 0.930 0.002 23.62 0.05 U 0.035 0.005 Feed Sprockets 1.050 26.67 W Intermittent sprockets 1.050 26.67 Hold-back sprockets 1.040 26.42 0.055 + 0 0.002 1.40 + 0 0.05BS5550-3.10.2:1980
32、 4 BSI 02-2000 Table 2 Dimensions for24-tooth universal sprockets (feed and hold-back) 1 2 3 4 5 Dimension Inches Approximate millimetre equivalents Angle A 1.124 0.001 28.55 0.025 B C 0.039 0.002 0.99 0.05 Standard dimensions Feed sprockets D Hold-back sprockets No part of the sprocket, other than
33、the teeth, shall be proud of the cylindrical surface of diameter D ! 15 0 1.0 R 0.077 1.96 S 0.004 0.10 “ 7 30 T Feed sprockets Recommended dimensions Hold-back sprockets W Feed sprockets 1.523 38.68 Hold-back sprockets 1.510 38.35 0.055 + 0 0.002 1.40 + 0 0.05 1.423 + 0.0015 0.0015 36.14 + 0.04 0.0
34、4 1.410 + 0.002 0.002 35.81 + 0.05 0.05 1.413 + 0.003 0.003 35.89 + 0.08 0.08 1.400 + 0.003 0.003 35.56 + 0.08 0.08BS5550-3.10.2:1980 BSI 02-2000 5 Table 3 Dimensions for32-tooth universal sprockets (feed and hold-back) 1 2 3 4 5 Dimension Inches Approximate millimetre equivalents Angle A 1.124.001
35、28.55 0.025 B C 0.039 0.002 0.99 0.05 Standard dimensions Feed sprockets D Hold-back sprockets No part of the sprocket, other than the teeth, shall be proud of the cylindrical surface of diameter D 11 15 0.75 R 0.077 1.96 S 0.004 0.10 “ 7 30 T Feed sprockets 1.887 0.004 47.93 0.10 Recommended dimens
36、ions Hold-back sprockets 1.869 0.004 47.47 0.10 W Feed sprockets 1.997 50.72 Hold-back sprockets 1.979 50.27 0.055 + 0 0.002 1.40 + 0 0.05 1.897 + 0.002 0.002 48.18 + 0.05 0.05 1.897 + 0.002 0.002 47.73 + 0.05 0.05BS5550-3.10.2: 1980 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstit
37、ution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions BritishStandards are updated by amendment or revision. Users of BritishStandards should
38、 make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this BritishStandard would inform the Secretary of the technical committee
39、responsible, the identity of which can be found on the inside front cover. Tel:02089969000. Fax:02089967400. BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standards. Buying standards Orders for all BSI, inter
40、national and foreign standards publications should be addressed to Customer Services. Tel:02089969001. Fax:02089967001. In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as BritishStandards, unless otherwise request
41、ed. Information on standards BSI provides a wide range of information on national, European and international standards through its Library and its Technical Help to Exporters Service. Various BSI electronic information services are also available which give details on all its products and services.
42、 Contact the Information Centre. Tel:02089967111. Fax:02089967048. Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards. For details of these and other benefits contact Membership Administration. Tel:020899670
43、02. Fax:02089967001. Copyright Copyright subsists in all BSI publications. BSI also holds the copyright, in the UK, of the publications of the international standardization bodies. Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retriev
44、al system or transmitted in any form or by any means electronic, photocopying, recording or otherwise without prior written permission from BSI. This does not preclude the free use, in the course of implementing the standard, of necessary details such as symbols, and size, type or grade designations
45、. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained. If permission is granted, the terms may include royalty payments or a licensing agreement. Details and advice can be obtained from the Copyright Manager. Tel:02089967070.
