Compared to other lifts found on robots, the two bar is one of the easiest and lightest lifts to build. Usually consisting of 4 c-channels (2 used for the tower and 2 for the lift), the two bars are usually used when a robot would like a lift, but one that does not take a lot of space. One of the main downsides and features of a two bar is that the orientation at the end of the lift stays constant despite lift angle. In addition, compared to other lifts, the two bar cannot carry as much weight compared to other lifts. Some examples of the usage of the two bar lift can be found in the game Tower Takeover as shown above.
Easy to build
Lack of height
Cannot carry a large amount of weight
Does not take up a lot of space
Orientation at the end of the lift changes with lift angle.
Make sure the c-channel is secured on the axle of the motor
Make sure the axle is secure in the motor.
If possible, use a gear ratio with a screw joint to reduce slop and increase torque of the motor.
With a similar appearance to a 2-bar, the chainbar has the compactivity of a 2-bar but with the capability to keep its mounting orientation constant throughout its movement.
This is done by adding a fixed orientation sprocket at the base of the lift bar, and then adding a free-turning one at the end of the lift bar with both being constrained by chain. If an intake or mechanism is mounted on the sprocket(s) at the end of the lift, the mechanism will maintain the same orientation throughout the lift's movement.
Very compact and lightweight
Non-Linear Movement (of the lift)
Moderate buildability, with it being comparable to a 2-bar but slightly harder to build
The maintenance might be slightly harder due to the chain needing to be tensioned.
Maintains fixed orientation for the mounted mechanism, unlike a 2-bar.
There is a chance the chain may break
during a match.
Best practices for 2-Bar also applicable here
Make sure chain is tight, avoid using mechanical tensioners as seen in picture above if possible to increase mechanical efficiency.
Try to keep the mounted intake or subsystem light, to reduce load on chain.
Example: NorCal 2021 Robot (View in .5x or full screen):
A cascade or elevator lift is a lift that provides an immense amount of height, while taking not a lot of space. It utilizes c-channels, sprockets, and chain to connect each bar together. These bars run parallel to the structural frame of the lift, which is connected to the chassis of the robot. Issues that are prevalent among cascade lifts is the lack of support found on the lift, as when fully extended, the linear characteristic of the cascade lift could cause issues in preventing the lift from failing. In addition, the difficulty in tuning and repairing cascade lifts due to its compactness makes it difficult for quick repairs or adjustments when failures do occur.
Very Linear Movement
Mechanically inefficient due to surface contact
Very compact relative to a bar lift
Relatively hard to build due to multiple stages in the lift
Mounting point can be easily made a flat surface.
Maintenance is an issue, as reattaching the chain means looping it around multiple sprockets in potentially hard to reach areas.
Reduce friction between the c-channels
Make sure the chain used is tight
Try to reduce weight of structural c-channels by using thinner c-channels or aluminum without degrading structural stability.
BLRS (Purdue SIGBots)