Many Do Not....
I must confess that I have never met one and wouldn't accept it if I was approached.
The nearest I've come to it is one the of these forums were it was mentioned that a rattle had developed as the cleats used to locate the end discs became detached.
I wouldn't have accepted those drums either. ■
Re: Function Of A Centre Disc Inside Pulley
The only reason for center discs is to reinforce the shell of the pulley. A thin pulley shell will deflect under the load of the belt tension. If your pulley design does not require this reinforcement then leave it out.
But on occasion you will get customers that will insist on it. Always best to please the customer?
Here is a good article on center disc design.
Attachments
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Gary Blenkhorn
President - Bulk Handlng Technology Inc.
Email: garyblenkhorn@gmail.com
Linkedin Profile: http://www.linkedin.com/in/gary-blenkhorn-6286954b
Offering Conveyor Design Services, Conveyor Transfer Design Services and SolidWorks Design Services for equipment layouts.
Stiffening To Engineering
The use of central stiffener ring plates at belt pulleys is certainly a engineering challenge. The use of stiffeners with stitched welding (onto the main web or flange plates) is a common feature in structural engineering of long girders. Cf. bridge crane girder engineering. However, stitched welds within pulleys don't seem to be a correct design decision due to the cyclic loading (vs. pulsating loading with girders). There's a fatigue strength issue.
With pulleys, there's the search for an design and cost optimum, somewhere the thickness of mantle plates meets a limit, where a leaner thickness + correctly welded stiffeners might be an option. Pls. note the slimness of the mantle plate in figure 2 of above article. Garys point about customer compliance is certainly a (the) most important point here, and it would imo be good if the know-how of such design would be present in your portfolio. Lest to support your argumentation.
Regards
R. ■
Pulley Center Disk
The original intent to use a single or more center disks was to control the pulley shell circular shape when the seam weld was applied. Bands of straps or chains were often used to assist pulling the shell seam joint before welding together.
Too many failed when a less than full penetration weld was applied due to the local stress risers. Most parties could not do the math until the FEA tools became available. Even then there is guess work. The benefits eventually were seen to be more risky, since so many did fail, sometimes in large quantities - Salt River comes to mine.
The center disk can provide a benefit to reduce the shell hoop stress, only if it is a full penetration weld applied as a continuous fillet, and given proper inspection treatment - mag particle, etc. This becomes too expensive. Better rolling techniques and machines fit-for-purpose , and better analysis techniques have replaced the devil for the present. ■
Function of a Centre Disc Inside Pulley
Function and Necessity of a Centre Disc inside Pulley
Many users of Conveyor Pulleys require a Centre Disc to be welded inside the Shell ( Usually it is only Stich Weld of a length of around 100 mm). we are manufacturers and suppliers of Belt Conveyor Pulleys and we feel that this is not required as in our opinion a properly designed End Disc and adequazte Shell thickness will suffice. We are also of the opinion that the centre disc does not necessarily provide any major purpose and to a certain extent induces stress on the shell at the points of the welding. I would like to know from the august members of the forum any design consideration to this effect and the actual use of the centre disc. ■