Talk:Mechanical 2.16.2009
After the completion of the Rally on Monday 2/16 and our ensuing mechanical team discussion ending at 11:45 PM regarding the issue of the present robot conveyor design’s inability to maintain the conveyor belts on the pulleys under adverse ball loading conditions I offer the following potential design alterations in remedation of the problem.
In consideration of the present physical and time constraints we could emulate a similar conveyor belting implementation as the Honeoye falls team by making 1.5” diameter x 21.87” long cylinders out of PVC, creating round belt paths at 1.75 inch centers using the belt material that the Honeoye team has graciously offered to supply us at no charge. Additionally replace the solid ¾ Aluminum shaft with ½ inch 1/16 wall Aluminum tubing for the top 3 front shafts and the 2 rear shafts, reducing weight and assembly/disassembly difficulty since ½” matches the diameter of the present conveyor shaft bearings.
Further considering, when we have the belt spacing at 1.5-2 inches the ball path opening probably has to be between 8-8.5 inches not to create excessive deformity of the balls leading to damage of the ball playing piece. With the present frame structure, bearing mounts and range of adjustment, we would need to reduce the pulley diameters for the new top 3 front row belt pulleys and top 2 rear row pulleys to approximately 1.5 inches. That would allow for a ball path opening with the adjustment we have to be a maximum of approximately 8.75 inches.
That would leave the plucker and divider setup on the front and lower conveyors all the same.
One thing that we may also consider is to then remove the 2 outer outside plucker belts from the inside of the frame to outside the frame and add more pluckers to the front lower shaft. This will eliminate throwing that belt which was the last event that occurred during the final test last night. It would also elimate having pluckers interfere into the drive belts.
In support of possibly moving the lower shaft belts out ouside of the gathering ball path, It was proven accidently during the short test last night, that the front pluckers by themselves can gather a ball and push it very easily up the conveyor path with no belts attached in the proximity of the plucker gathering entrance as balls accidently entering that side and would then be thrown back out of the front of the robot hitting TomC as he was manually feeding balls into the gathering input:)
Are there any other thoughts in regard to the above?
Estimated required materials for the above redesign if decided to pursue by the team
Notes:
- If PVC pipe is used for the rollers then item 2 would not be required - Might be a weight problem.
- If we manufacture belts in some other fashion items 4 and 5 would not be required.
| Item | Description | Manufacture | Part Number | Quantity | Cost |
|---|---|---|---|---|---|
| 1 | Multipurpose Aluminum (Alloy 6061) Tube 1/2" OD, .370" ID, .065" Wall Thickness, 6' Length | McMaster Carr | 9056K661 | 2 | $56 |
| 2 | Multipurpose Aluminum (Alloy 6061) Tube 1-1/2" OD, 1.370" ID, .065" Wall Thickness, 6' Long | McMaster Carr | 9056K791 | 2 | $104 |
| 3 | Black Nylon 6/6 Rod 1-1/2" Diameter x 2' Long (Black) | McMaster Carr | 8541K27 | 2' | $18 |
| 4 | Urethane Hollow Core Round Belting Yellow, 3/16" OD, 1-1/2" Minimum Pulley Diameter x 200' Long | McMaster Carr | 6567K56 | 200' | $122 |
| 5 | Aluminum Connector for 3/16" Outside Diameter Urethane Hollow Core Round Belting This product is sold in Packs of 25 | McMaster Carr | 6567k26 | 4 | $20 |
