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 conveyors with profiles Post Reply Forum
 Posted by: sean123456 ® 06/15/2004, 22:46:01 Author Profile Mail author Edit I have a timing belt that has a 1-1/4 profile, which pushes a block along a rail to another conveyor. The speed of the conveyor is 1218.75 in/min. My boss told me to determine the rpms by taking the distance from the center of the shaft to the end of the profile. I told him that I need to determine the pitch diameter of the pulley and thats how I will determine my required rpms to achieve the correct speed of the conveyor. My theory is that if I do it his way the radial speed will be 1218.75 in/min, but the linear speed will be less. How can I prove this to him with a formula or something to help him see the light. Thank you for your responce.

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 Re: conveyors with profiles Re: conveyors with profiles -- sean123456 Post Reply Top of thread Forum
 Posted by: acroduster1 ® 06/16/2004, 09:00:05 Author Profile Mail author Edit Draw a picture showing two parallel lines coming to the pulley representing the top and bottom of the belt.  Continue the lines wrapping around the pulley.  On the straight section of belt, draw a perpindicular line from the top of the belt to the bottom.  On the curved section of belt, draw a several radial lines from the outside of the belt to the inside that touches the pulley.  Explain to your boss that on the straight section of belt, all points on that line drawn are moving at the same speed.  On the curved section of the belt, the points on those lines nearest the shaft are moving slower than the points farther away, but the only point that is moving at the same speed as the whole line on the straight section of belt is the middle (for a homogenous, elastic, constant cross-section belt).  When the belt hits the tangent of the pulley, the outer fibers speed up, the inner fibers slow down, but the middle stays at the same speed as the entire belt.  Maybe this graphical representation will help him... Acro