Powered Roller Conveyor

[rocksolid]

I was wondering if anybody knew of a good way to design a powered roller conveyor with rollers being quite small and close together. My roller diameter is 3/4". My center spacing is 1" roller to roller. I have to achieve a roller surface speed of approx. 215 FPM. My roller face length is 36" wide. I have tried some different ways, but am unhappy with all results so far. I have means of powering this via
AC OR DC Motor. I can even use air. If need be I may be able to power everyother roller, but would really like to power every one. Any suggestions would be much appreciated.
Thanks,
Rocky

 

[ddmemphis]

Based on the small diameter rollers and close roller centers, there are only a few common ways to power the rollers.

The most common method is to use a flat belt, maybe about 12" wide, with a second set of "pressure" rollers under the belt, maybe on 3" centers, to drive the tread rollers. This style is used at many different speeds and lengths. Normally, due to OSHA regulations, the rollers are required to be in a slotted frame; however, with such close roller centers, you may be able to use punched frames to hold the rollers at a constant height above the frame.

Another style, similar to this, uses a v-belt off to one side of the unit with sheaves to push the belt up against the tread rollers. This style can be used at many different speeds, but the length of the unit is sometimes limited by the v-belt. It tends to loose its driving force the farther you get from the drive.

A variation of the v-belt driven style uses a round cable under the tread rollers. It can be run at many different speeds and the units can be made in many lengths.

Since all of these units have a round pulley or sheave at each end of the unit, they will all require that the last 2 or 3 tread rollers at each end of the unit have a groove in them if you want them to be driven. This may prove to be a problem for a 3/4" diameter roller.