Parker Pneumatic has developed the unique, single unit PTO Selector Valve to control the engagement and disengagement of power take off (PTO) on commercial vehicles.Working in partnership with leading European truck industry systems manufacturers, Parker Pneumatic has developed the unique, single unit PTO Selector Valve to control the engagement and disengagement of power take off (PTO) on commercial vehicles. With the growth of heavy commercial vehicles such as mobile cranes, loaders and tankers, PTO plays an increasingly important role. Power take off is a truck industry term for an auxiliary gearbox which is driven through the vehicle's main transmission to provide power to drive hydraulic pumps, fan blowers and other ancillary equipment.
Selection and deselection of the PTO function is a safety critical operation with the potential to cause injury to the operator and passers-by, or to cause expensive damage to the PTO or the main transmission system.
Perfect manual interface with the control system is essential to achieve a safe interlock, eliminating the possibility of human error.
A common cause of damage and potential injury identified by Parker Pneumatic relates to PTO engagement, via a latching type of electrical switch, when the system remains operational until manually released.
Deselection of the interlock via the release of a park brake or speed sensing unit selects a disengaged status for the PTO.
If the operator or driver is unaware of this deselection, the next time the park brake is applied or speed is reduced, the PTO will try to engage, causing damage to the PTO or main transmission and possibly creating a potential hazard for passers-by.
As a leader in the development and manufacture of driveline controls for the heavy truck industry, Parker Pneumatic turned its attention to providing a solution to the problems of PTO control.
Initial research in the UK and European truck markets identified the underlying requirements and the Parker team started on the development of the unique PTO Selector Valve, bringing to bear the group's experience in the field of electro-pneumatic control.
Parker Pneumatic's PTO Selector Valve combines both electronic and pneumatic functions and incorporates important safety features for the protection of operator personnel, other road users and the general public, and to prevent mechanical damage to the PTO and drive chain.
The PTO Selector Valve provides a fail-safe interlock system designed to be applied to both stationary and/or moving vehicle power take off applications.
The PTO Selector Valve also includes functions for signalling engine management systems, linking with an emergency stop and in-operation warning lights or audible klaxons.
Designed and built to IP68, the unit, connectors and cable are of non-corrosive materials to enable chassis mounting in the vicinity of the vehicle's PTO, fulfilling an important requirement identified by bodybuilders.
The electrical switch is of non-latching design, ensuring that in the case of automatic deselection of the interlock, further engagement of the PTO will not occur until manual reselection has taken place.
The PTO Selector Valve incorporates a full interlock system, requiring only connection to the interlock source.
For truck OEMs, this significantly reduces the number of relay and switch components to source, stock and install.