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This mechanism is a two person venture into building a structure and actuation system to act as a moving cloud for the 2018 Cal Poly Rose Float. As one of the largest mechanisms on the Rose Float coming in at 15 feet long and 10 feet wide, it's been a massive undertaking, especially considering the numerous interferences the mechanism poses with other structures on the float. The biggest challenge though: designing it to move hundreds of pounds of material inches above two float operators heads.
The original prototype built to demonstrate proof of concept to the rest of the team.
Here you see an initial sketch of the layout of the mechanism as it is placed over the float chassis. One change we made in our build process was the decision to move the crankshaft from the front (the right in this photo) to just to the right of the pushrod-rocker mechanism.
Pictured above: The hydraulic circuit which powers the mechanism.
Pictured above: The support structure for the front half of the pod.
The panhard rod for our mechanism which prevents lateral movement.
Pictured above: The central structure of the front pod. The entire front structure is supported and balanced on a 1" diameter spherical bearing allowing for the rolling/rotational motion required of the mechanism.
Actuation of the front pod is provided by a crank mechanism powered by the under-mounted red hydraulic motor. The motor is offset from the crankshaft with a chain drive sprocket system which provides a gearing ratio of 3:1. The hydraulic motor is governed with a pressure compensated flow control valve to achieve a speed of 48RPM. The rear plate is coupled to the front actuation mechanism by a pushrod-rocker mechanism, giving the rear plate a contrasting seesaw motion. Pins are built in to allow the structure to be locked in place in 90 degree increments as the float is worked on.
A pushrod-rocker mechanism drives motion from the crankshaft to the rear section of the pod in order to provide contrast to emphasize the motion of the cloud.
The rear section of the pod. This structure moves in a seesaw motion by pivoting on two pillow blocks. The seesaw motion gives the two sections of the pod a greater contrast and visual effect as they move opposite of one another.
Because we decided to use an old hydraulic cylinder shaft as the crankshaft for our mechanism (just for fun!), we also had to deal with the medium carbon steel it was made out of. Therefore, the shaft required preheating before welding to ensure a structurally sound weld.
Pictured above: Both the front and rear sections of the mechanism can be seen mounted on the Rose Float chassis. Notice the position of the front section of the structure in relation to the two operators on either side of the chassis.
After spraying 6-10 inches of expanding foam across the entire base of the float, the cloud is now beginning to really take shape.
Safety was a major concern with this mechanism, as it moves hundreds of pounds of material inches above two float operators heads. Several hard stops were set in place in case of catastrophic failure. Also, as you can see in this photo, we implemented a safety cage made of chicken wire to protect the operator from any pinch points. Shut off valves further allowed the operators to shut off the mechanism from their compartment.
Something that most people don't have the opportunity to see is the underlying workings of a Rose Float. Here is a video of the underlying mechanism which powers the motion of the cloud mechanism.
Here is a video of the float in its completion during our judging which takes place the day before the actual parade. At the front of the float you can see the cloud mechanism in action as it rolls under Paula the Koala's plane.
And here is KTLA's coverage of our float as it travels down Colorado Boulevard in the 2018 Rose Parade.
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