How to Select a BF (between frame)

Usually a conveyor’s BF, or between frame dimension, should be about 2" wider than the widest package. However, there are other considerations when specifying a BF. If a conveyor has its rollers or wheels set hi in the frame (roller surface above the frame which is standard), then packages can extend beyond the width of the frame as long as they remain stable and will not collide with any external objects. Also if there is a curved section of conveyor in the system then the BF will likely need to be wider, as a package will require more width to travel around a curve then it will when traveling straight. This is similar to a large truck making a turn, it will need more room to make a turn than when traveling straight.

Ashland Conveyor curves are designed with a different inside radius depending upon the frame size. The inside radius remains constant while the outside radius will vary depending upon the BF. Conveyor frames with 2-1/2" channel have a standard 36" inside radius, 3-1/2" frames are 30", and 4" frames are 32-1/2". Curves with a non-standard inside radius can be designed when required.

There is a formula that can be used to determine the BF when a curve is needed. The formula allows for 2” of clearance. Also provided are tables for the different sized frames that will provide the appropriate BF depending upon the packager’s length and width. The results in the tables also include 2” of clearance. If the conveyor is to be set low or have guards mounted than the curve BF must be calculated using the formula or appropriate table.


Conveyor Curve Clearance Formula

 Curve Clearance

2-1/2" Channel (36" Inside Radius)

Product Length

Product Width
4" 8" 12" 16" 20" 24" 28" 32" 36"
Minimum Between Frame Dimension
4" 6" 10" 14" 18" 22" 26" 30" 34" 38"
8" 6" 10" 14" 18" 22" 26" 30" 34" 38"
12" 6" 10" 14" 18" 22" 26" 30" 34" 38"
16" 7" 11" 15" 19" 23" 27" 30" 34" 38"
20" 7" 11" 15" 19" 23" 27" 31" 35" 39"
24" 8" 12" 15" 19" 23" 27" 31" 35" 39"
28" 8" 12" 16" 20" 24" 28" 32" 35" 39"
32" 9" 13" 17" 20" 24" 28" 32" 36" 40"
36" 10" 14" 17" 21" 25" 29" 32" 36" 40"

 

3-1/2" Channel (30" Inside Radius)

Product Length

Product Width
4" 8" 12" 16" 20" 24" 28" 32" 36"
Minimum Between Frame Dimension
4" 6" 10" 14" 18" 22" 26" 30" 34" 38"
8" 6" 10" 14" 18" 22" 26" 30" 34" 38"
12" 6" 10" 14" 18" 22" 26" 30" 34" 38"
16" 7" 11" 15" 19" 23" 27" 31" 35" 38"
20" 7" 11" 15" 19" 23" 27" 31" 35" 39"
24" 8" 12" 16" 20" 23" 27" 31" 35" 39"
28" 9" 12" 16" 20" 24" 28" 32" 36" 39"
32" 10" 13" 17" 21" 24" 28" 32" 36" 40"
36" 10" 14" 18" 21" 25" 29" 33" 37" 40"
40" 11" 15" 19" 22" 26" 30" 33" 37" 41"
44" 12" 16" 19" 23" 27" 30" 34" 38" 42"
48" 14" 17" 20" 24" 27" 31" 35" 38" 42"
52" 15" 18" 21" 25" 28" 32" 36" 39" 43"

 

4" Channel (32-1/2" Inside Radius)

Product Length

Product Width
4" 8" 12" 16" 20" 24" 28" 32" 36"
Minimum Between Frame Dimension
4" 6" 10" 14" 18" 22" 26" 30" 34" 38"
8" 6" 10" 14" 18" 22" 26" 30" 34" 38"
12" 6" 10" 14" 18" 22" 26" 30" 34" 38"
16" 7" 11" 15" 19" 23" 27" 31" 34" 38"
20" 7" 11" 15" 19" 23" 27" 31" 35" 39"
24" 8" 12" 16" 19" 23" 27" 31" 35" 39"
28" 9" 12" 16" 20" 24" 28" 32" 36" 39"
32" 9" 13" 17" 21" 24" 28" 32" 36" 40"
36" 10" 14" 18" 21" 25" 29" 33" 36" 40"
40" 11" 15" 18" 22" 26" 29" 33" 37" 41"
44" 12" 16" 19" 23" 26" 30" 34" 38" 41"
48" 13" 17" 20" 24" 27" 31" 35" 38" 42"
52" 14" 18" 21" 25" 28" 32" 35" 39" 43"