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[Technical Data]
            Selection of Conveyor Timing Belts




          ■Conveyer belts selection procedure        [Step 4] Determine belt length (no. of teeth) and center distance.
          The following steps for selection is based on the case that sizes of head pulley and tail pulley are same.  (1) Obtain approximate belt length from tentative center dimension (C') and approximate pulley diameter (Dp').
          (Follow the steps 1 -3 even when sizes of head pulley and tail pulley are different)     Lp' (mm)   Approx. belt length

          Use a head pulley as a driving pulley.       Lp’=2·C’+Q·Dp’       C'  (mm)   Tentative center dimension
          For belt installation and tension control, make the structure of the driven side to be      Dp'(mm)   Approx. pully diameter
          adjustable of alignment and center distance with set screws.
          ※ Head Pulley: The front of the pulley against traveling direction   (2) Determine the number of teeth required from the approximate belt length (Lp') and pitch (P).
           Tail Pulley: The rear end of the pulley against traveling direction     Round down the obtained number of teeth (N) to the nearest whole number.
          [Step 1] Calculate effective tension (Te).    N=Lp’/P             N      No. of belt teeth
                                                                                   Pitch
                                                                            P  (mm)

                                                     *Check the minimum teeth of belt which is available.
             Traveling Direction  Head pulley (Driving Pulley)  (3) Obtain the proper belt length from the number of teeth (N) and pitch (P).
                                Te= 9.8(μ·G+G·H/C)
                                                       Lp= P·N
                                                                                   Belt length
                                                                            Lp (mm)
                               H                     (4) Determine proper center distance with the following formula:
                                Te (N)   Effective tension
                                G  (Kg)   Net weight of load placed on the belt surface    C= P·(N-Dz)/2   C  (mm)   Center Distance
                                O     Friction coefficient of belt vs. table (Table 1)     Dz     No. of teeth of pulley
                       C        H  (mm)   Lift
          Tail pulley           C  (mm)   Tentative center dimension (conveyor length)  [Step 5] Confirm the ajustment margin for the center distance is larger than figures in Table7-a and 7-b.
          Table 1. Typical Friction Coefficient of Belt versus Table
          Table Material  Steel  Stainless  Aluminium  UHMW  Teflon
          Friction coefficient: O  0.65  0.68  0.42  0.31  0.21
          [Step 2] Calculate design tension (Td).              Center Distance
            Td=K·Te             Td  (N)  Design Tension       Inner Adjustment Allowance  Outer Adjustment Allowance

                                K
                                     Overload Coefficient
                                Te  (N)  Effective Tension  Table 7-a: Inner Adjustment Allowance (Attachment Allowance) Table 7-b: Outer Adjustment Allowance (Tension Allowance)
            K=K1+K2+K3          K1   Correction factors for daily operation hours  Belt Type  Inner Adjustment Allowance  Distance between shafts (mm) Outer Adjustment Allowance
                                                         XL

                                K2
                                                               More than 5mm
                                                                               ~ 500
                                                                                      More than 5mm
                                     Belt length correction coefficient
                                K3   Belt speed correction coefficient  L  More than 10mm  501~1000  More than 10mm
                                                         H     More than 15mm  1001~1500  More than 15mm
          Table 2. K1  Correction Factors for Daily Operation Hours Unit: hour  S3M  More than 5mm  1501~2000  More than 20mm
             ~5      5~8     8~12    12~16   16~24      S5M    More than 10mm  2001~2500  More than 25mm
             1.0     1.1      1.2     1.3      1.4      S8M    More than 15mm  2501~  1% of center distance
                                                         T5    More than 5mm
          Table 3. K2  Belt Length Correction Factors  Unit : mm  T10  More than 10mm
           ~1500   1501~3000  3001~4500  4501~          H3M    More than 5mm
             0.3     0.2      0.1     0.0               H5M    More than 10mm
          Table 4. K3   Belt Speed Correction Factors  Unit : m/min  H8M  More than 15mm
            ~60     61~90   91~120                   [Step 6] Install timing belt.
             0.0     0.1      0.2
          [Step 3] Select belt type, belt width and pulley dimension.  Install the belt with the installation tension in Table 8.
                                                        Axis weight at this time is twice the installation tension.
          ①Select from Table 5 a belt type and a width which have a greater allowable tension than the designed tension.  Fs=2·Ti   Fs    (N) Shaft load
          Table 5.  Allowable Tension of Joint Belts  Unit : N              Ti     (N) Fixing Tension (Table 8)
           Belt              Belt Width(mm)          Table 8. Installation Tension for Joint Belts
           Type  6   9  10  12  15  20  25  30  40  50                   Belt Width(mm)
           S3M   70  -  80  -  110  -  -  -   -  -   Belt Type  6  9  10  12  15  20  25  30  40  50
           S5M   -  -   165  -  230  -  400  -  -  -   S3M   35     40     55
           S8M   -  -   -   -  240  -  450 530 650  -            -      -      -  -   -   -  -
            T5   -  -   150  -  200 270 350  -  -  -   S5M   -   -  83  -  115  -  200  -  -  -
           T10   -  -   -   -  320 440 640 720 960 1280  S8M  -  -  -   -  120  -  225 265 325  -
           H3M   70  80  -  90  -  -  -   -   -  -      T5   -   -  75  -  100 135 175  -  -  -
           H5M   -  165  -  -  230  -  400  -  -  -    T10   -   -  -   -  160 220 320 360 480 640
           H8M   -  -   -   -  -  360 450 530 650  -   H3M   35  40  -  45  -  -  -   -   -  -
          ②Select a pulley with a larger number of teeth than the minimum allowable number in Table 6 for both of driving and driven pulley.  H5M  -  83  -  -  115  -  200  -  -  -
                                     Unit : mm         H8M   -   -  -   -  -  180 225 265 325  -
                       Belt Nominal Width
          Belt Type                                                              Unit : mm
                 025 037 050 075 100 150 200
            XL   70  80  110  -  -  -   -            Belt Type    Belt Nominal Width
            L    -   -  200 300 400 600  -                   025 037 050 075 100 150 200
            H    -   -   -  300 400 600 800             XL   35  40  55  -  -   -  -
          Table 6. Number of Minimum Allowable Number of Teeth for Pulleys  L  -  -  100 150 200 300  -
          Belt Type  XL  L  H S3M S5M S8M T5 T10 H3M H5M H8M  H  -  -  -  150 200 300 400
          Pitch (mm) 5.08 9.525 12.7  3  5  8  5  10  3  5  8
          Min. No. of Pully Teeth 12  14  14  14  14  24  12  14  14  14  24
          Pully Diameter (mm) 19.40 42.45 56.60 13.37 22.28 61.12 19.10 44.56 13.37 22.28 61.12
          Reference: Open End Belt Allowable Tension Table   Unit : N                       Unit : N
          Belt                Belt Width(mm)                                  Belt Nominal Width
          Type  Material  6  9  10  12  15  20  25  30  40  50  Belt Type  Body Material  025  037  050  075  100  150  200
          S3M Urethane 127  -  145  -  159  -  -  -  -  -  XL   Urethane  127  145  159  -  -  -  -
          S5M Urethane  -  -  215  -  323  -  539  -  -  -  L   Urethane  -  -  270  404  539  809  -
          S8M Urethane  -  -  -  -  647  -  1176 1412 1882  -  H  Urethane  -  -  -  404  539  809  1078
           T5  Urethane  -  -  196  -  291  394  497  -  -  -
          T10 Urethane  -  -  -  -  523  695  926  1097 1509 1862
          H3M Urethane 127  145  -  150  159  -  -  -  -  -
          H5M Urethane  -  215  -  -  323  -  539  -  -  -
 1595     H8M Urethane  -  -  -  -  -  941  1176 1412 1882  -                                     1596
           When using belts for other purpose than conveyance (e.g. transmission), for polyurethane belt S3M/H3M; design with 1/2 of the allowable tension in the table; for XL, L, H, S5M, S8M, T5, T10, H5M and H8M, design with approx. 2/3 of the allowable tension in the table.
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