1、BRITISH STANDARD BS 6889:1987 Specification for Generating racks for synchronous belt drive pulleys UDC 621.852.86.05BS6889:1987 This British Standard, having been prepared under the directionof the Machinery andComponents Standards Committee, was published underthe authority of the BoardofBSI and c
2、omes intoeffecton 30 November1987 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference MCE/10 Draft for comment 86/74323 DC ISBN 0 580 16178 1 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the M
3、achinery and Components Standards Committee (MCE/-) to Technical Committee MCE/10, upon which the following bodies were represented: Agricultural Engineers Association British Coal British Gear Association British Rubber Manufacturers Association Society of Motor Manufacturers and Traders Limited Am
4、endments issued since publication Amd. No. Date of issue CommentsBS6889:1987 BSI 10-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Dimensions and tolerances 1 Figure 1 The profile of the generating rack 1 Table 1 Dimensions and tolerances for r
5、acks for generating grooves in pulleys 2 Publications referred to Inside back coverBS6889:1987 ii BSI 10-1999 Foreword This British Standard has been prepared under the direction of the Machinery and Components Standards Committee. It specifies the dimensions and tolerances for racks used to generat
6、e the groove profile on pulleys as used in various industrial synchronous belt drive systems included in BS 4548:1987. It also includes racks for pulleys for automotive belt drives (pitch code ZA) as specified in BS AU 218. Because this particular aspect of manufacture of synchronous belt drives is
7、primarily confined to one sector of the industry, it is more convenient to include the requirements for all racks in one standard. The requirements for racks for industrial pulleys were previously described in BS4548:1970 but are excluded from the 1987 revision of that standard. This standard for ra
8、cks is aligned with the dimensional details of BS 4548:1987 and BS AU 218, all of which are as agreed in discussions in the International Organization for Standardization (ISO). A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are
9、responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi and ii, pages1and 2, an inside back cover and a back cover. This standard has
10、 been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS6889:1987 BSI 10-1999 1 1 Scope This British Standard specifies the dimensions and tolerances for racks that are used for generating grooves in pulle
11、ys for synchronous belt drives. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this British Standard, the following definitions apply. 2.1 generating rack profile the shape of the generating rack (see Figure 1) 2
12、.2 pitch code a code designating different sections of belts and associated pulleys (see Table 1) 3 Dimensions and tolerances The dimensions and tolerances for racks for generating grooves in types of pulleys as defined by the appropriate pitch code shall be as given in Table 1. NOTEThis figure show
13、s the symbols assigned to the various dimensional parameters specified. Figure 1 Profile of the generating rackBS 6889:1987 2 BSI 10-1999 Table 1 Dimensions and tolerances for racks for generating grooves in pulleys Pitch code Number of grooves in pulley P b A h r b g r 1 r 2 2a 0.003 0.0001 0.12 +0
14、.05 0 +0.002 0 +0.05 0 +0.002 0 0.03 0.001 0.03 0.001 XL 10 and over mm 5.080 in 0.2000 degrees 25 mm 1.40 in 0.055 mm 1.27 in 0.050 mm 0.61 in 0.024 mm 0.61 in 0.024 mm 0.508 in 0.020 L 10 and over 9.525 0.3750 20 2.13 0.084 3.10 0.122 0.86 0.034 0.53 0.021 0.762 0.030 H 14 to 19 12.700 0.5000 20 2
15、.59 0.102 4.24 0.167 1.47 0.058 1.04 0.041 1.372 0.054 20 and over 1.42 0.056 XH 18 and over 22.225 0.8750 20 6.88 0.271 7.59 0.299 2.01 0.079 1.93 0.076 2.794 0.110 XXH 18 and over 31.750 1.2500 20 10.29 0.405 11.61 0.457 2.69 0.106 2.82 0.111 3.048 0.120 MXL 10 to 23 2.032 0.0800 28 0.64 0.025 0.6
16、1 0.024 0.30 0.012 0.23 0.009 0.508 0.020 24 and over 20 0.67 0.0265 ZA 19 and over 9.525 20 2.13 3.10 0.86 0.71 1.372 BS6889:1987 BSI 10-1999 Publications referred to BS 4548, Specification for synchronous belt drives for industrial applications 1) . BS AU 218, Specification for automotive synchron
17、ous belt drives 1) . 1) Referred to in the foreword only.BS 6889:1987 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level
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