US Patent 10407288 Leveling system for lift device

A lift device includes a chassis, a rear leveling assembly coupled to a rear end of the chassis, and a front leveling assembly coupled to a front end of the chassis. The rear leveling assembly includes a first rear actuator and a second rear actuator. The first rear actuator and the second rear actuator are selectively engageable to facilitate providing active control of a rear pitch adjustment and a rear roll adjustment of the rear leveling assembly. The front leveling assembly includes a first front actuator and a second front actuator. The first front actuator and the second front actuator are (i) selectively fluidly couplable to facilitate providing passive control of a front pitch adjustment and a front roll adjustment of the front leveling assembly and (ii) selectively fluidly decouplable to facilitate providing active control of the front pitch adjustment and the front roll adjustment of the front leveling assembly.