The Rocketbox PTO is a shifting transmission designed to send
power out to either of two output shafts, independently. PTO
stands for "Power Take Off" and is a term commonly used for mechanisms
which can switch supplied power from one shaft over to another. On our
Rocketbox, one shaft is intended to provide power to a robot
drivetrain (aka: Drive Output Shaft) while the second shaft may power
separate appendage, arm, winch, or any other mechanism (aka: Mechanism
Shaft). Both output shafts cannot be powered at the same time.
Gears can be swapped in and out on the second stage of the Rocketbox PTO, much like our Toughbox Mini. To change ratios, simply change the small cluster gear and the large output gear that is on the shifting shaft.
transmission is shipped assembled, not as a kit. However, this
transmission has the ability to be rebuilt into a mirror image of
side plates are identical and reversible, allowing users to have
concentric Mechanism Shafts when installed on each side of the
drivetrain. Also unique
to this transmission is the inclusion of a spring-extended air cylinder
which performs the shifting action. This cylinder requires air
pressure to actuate the dog shifting mechanism to transmit torque from
the Drive Output Shaft or the Mechanism Shaft.
- Two output shafts (Drive Shaft and Mechanism Shaft) positioned on opposite sides of the transmission are utilized, with only one driven at a time
- One or two CIM Motor input
- Wide variety of gear ratio and shaft options available
- Can be reassembled in mirrored geometry
- Air cylinder included
to the large amount of forces and torques involved in shifting this
PTO, pneumatic shifting is recommended. The spring extended, Bimba
040.5-RP Air Cylinder with nut (am-0591)
is the preferred cylinder for this transmission. If air pressure is
lost, the spring pushes the cylinder and dog shift gear into the Drive
Output Shaft on the plate opposite from the motors. This shift method
in under 0.5 seconds, with 26 pounds of force (if using 60 psi). This
pneumatic shift can be done while the transmission is accelerating or
- Weight: 5.24 pounds
- Output shaft size: 1/2" hex, 4140 steel
- Housing material: 6160 Aluminum
- Gear Material: 4140 Steel
- Shaft Material: 4140 Steel
- Shifting Method: Dog gear sliding on hex shaft, actuated by pneumatic cylinder
- Includes one E4T Miniature Optical Encoder Kit (am-3132)
Attached Hardware (Excluding Gearing):
Gear Stages and Ratios:
This transmission consists of three gear stages:
- The first stage includes two 14T CIM gears (am-0034) and a 50T Cluster Gear (am-0149)
- The second stage is where the gears can be changed to provide various gear ratios. The customer can order one ratio and then purchase extra, optional gears in order to get different ratios. Final output ratios are listed here (with the second stage gear pair):
third stage transmits power from the shifting shaft onto either of the
output shafts. This ratio is 1:1, with 35T gears on
both shafts. The dog shifter on the shifting shaft selects which output
shaft to send power.
This products accepts up to 2 CIM motors.
gearboxes require grease for proper operation and long life. We suggest
using our red tacky grease, am-2768. We also encourage that the user
powers the gearbox continuously for 30 minutes without grease to allow
the gear teeth to wear in. While we do design with short run times in
mind, this 'run in' period for smooth gearbox operation, is recommended.
Once this is completed, thorough grease of the gear teeth periodically
to ensure smooth operation.