Abstract: A hydraulic cylinder assembly includes a cylinder and a piston rod. The cylinder has an opening and upper and lower inner walls formed by a bore. An end of the piston rod is received in the bore through the opening and travels reciprocally through the opening in response to volume change of a hydraulic fluid in the cylinder. The cylinder has a first section adjacent the opening provided with a narrow passage of the piston rod close to the cylinder upper inner wall. The cylinder has further a second section spaced apart from the opening and provided with a clearance between the piston rod and the lower inner wall forming a chamber for the hydraulic fluid. The inner upper wall at the first section is provided with circumferential camberings.

Abstract: Method for cleaning hydraulic liquid in a industrial truck, wherein said industrial truck is an electrically powered industrial truck having a battery as an energy source with a hydraulic system comprising, a hydraulic pump, a hydraulic reservoir, and a return pipe to the hydraulic reservoir with a return filter, wherein the method comprises the steps of, the hydraulic pump is activated for hydraulic activity, the hydraulic pump pumps the liquid for the hydraulic activity and in relation to this return flow through the return filter to the hydraulic reservoir occurs, the hydraulic pump can be activated by means comprised in the industrial truck, when hydraulic activity is not present, by that achieving a circulation to the hydraulic reservoir through the return filter such that sufficient filtration of the hydraulic liquid is reached, further a time Tb for circulation without hydraulic activity can be accumulated and/or a sensor for determining the quality of the hydraulic oil can be arranged in the industria

Abstract: A hydraulic cylinder assembly includes a cylinder and a piston rod. The cylinder has an opening and upper and lower inner walls formed by a bore. An end of the piston rod is received in the bore through the opening and travels reciprocally through the opening in response to volume change of a hydraulic fluid in the cylinder. The cylinder has a first section adjacent the opening provided with a narrow passage of the piston rod close to the cylinder upper inner wall. The cylinder has further a second section spaced apart from the opening and provided with a clearance between the piston rod and the lower inner wall forming a chamber for the hydraulic fluid. The inner upper wall at the first section is provided with circumferential camberings.

Abstract: Method for cleaning hydraulic liquid in a industrial truck, wherein said industrial truck is an electrically powered industrial truck having a battery as an energy source with a hydraulic system comprising, a hydraulic pump, a hydraulic reservoir, and a return pipe to the hydraulic reservoir with a return filter, wherein the method comprises the steps of, the hydraulic pump is activated for hydraulic activity, the hydraulic pump pumps the liquid for the hydraulic activity and in relation to this return flow through the return filter to the hydraulic reservoir occurs, the hydraulic pump can be activated by means comprised in the industrial truck, when hydraulic activity is not present, by that achieving a circulation to the hydraulic reservoir through the return filter such that sufficient filtration of the hydraulic liquid is reached, further a time Tb for circulation without hydraulic activity can be accumulated and/or a sensor for determining the quality of the hydraulic oil can be arranged in the industria

Abstract: Method to control the lowering movement of the lifting cylinder or cylinders (1, 2) of a truck. When a lowering is to take place the pump (5) is started in the pumping direction for increasing the pressure between the pump and a loadholding valve (3, 4) until essentially the pressure has been achieved as in the hydraulic cylinder (1, 2), whereafter the pump with its motor is switched over to regenerative operation, that is the pump works as motor and the motor as generator. The holding valve (3, 4) is opened so that the oil while driving the pump can flow back through this.

Abstract: Method to control the lowering movement of the lifting cylinder or cylinders (1, 2) of a truck. When a lowering is to take place the pump (5) is started in the pumping direction for increasing the pressure between the pump and a loadholding valve (3, 4) until essentially the pressure has been achieved as in the hydraulic cylinder (1, 2), whereafter the pump with its motor is switched over to regenerative operation, that is the pump works as motor and the motor as generator. The holding valve (3, 4) is opened so that the oil while driving the pump can flow back through this.