Variation of forklift speed or fork lowering speed by controller dependent upon weight on forks

摘要

A fork lift truck (100) includes a body (110), a drive mechanism (120) supported on the body for effecting movement of the body, and a fork carrying assembly (155, 170, 175, 180) carrying forks (150) which can be moved in height between a lowered position and desired raised positions. A tilt cylinder (200) is provided for tilting the forks through a fork tilt range. The truck further includes a pressure sensor (210) capable of generating signals indicative of the weight of a load on the forks, a fork tilt position sensor (250) capable of being activated when the forks are titled to extremes of the fork tilt range, and a controller (not shown). The controller is coupled to the drive mechanism, the pressure sensor and the fork tilt position sensor. It causes the drive mechanism to effect movement of the body up to a first maximum speed when at least one of the pressure sensor generates a signal indicative of a load on the forks having a weight above a predetermined value and the tilt position sensor is activated, and causes the drive mechanism to effect movement of the body up to a second maximum speed which is greater than the first maximum speed when the pressure sensor generates a signal indicative of no load or a load on the forks having a weight below the predetermined value and the tilt position sensor is inactivated. The lowering speed of the forks can also or alternatively be increased under the same operating conditions.