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US 5,638,387 AGranted
Electrically driven lift truck
AssigneeFiat Om Carrelli Elevatori S.p.A.
InventorsGuido Palleggi, Fabrizio Lanza
Life of this patent
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Abstract
A lift truck has a tractive-power electric motor, an electric motor which actuates a pump for the hydraulic circuits, and batteries which supply the electric motors. In order to obtain a long working life as well as reliability and a high performance, the tractive-power motor or both motors are asynchronous and there are provided devices for sensing the angular positions and angular velocities of the motors and an electronic control unit connected to the sensor devices for controlling the power supplies to the motors in dependence on required velocities for the motors and on the basis of data provided by the sensor devices.
Claims18
An electrically driven lift truck comprising:
- (a) at least one electric motor for providing tractive power for drive wheels of the truck;
- (b) an electric motor for actuating a pump which supplies hydraulic circuits of the truck;
- (c) a dc power supply for supplying the electric motors, wherein the at least one electric motor for providing the tractive power or both electric motors are asynchronous motors;
- (d) an angular position sensor means for measuring the angular position of the asynchronous motor;
- (e) an angular speed sensor means for measuring the angular speed of the asynchronous motor;
- and
- (f) an electronic control unit connected to the angular position sensor means and the angular speed sensor means, wherein the electronic control unit controls the power input to the asynchronous motor, the power input being dependent on required speeds of the asynchronous motor and data provided by the angular position sensor means and the angular speed sensor means.
4 more elements
An electrically driven lift truck comprising:
- (a) at least one electric motor for providing the tractive power for the drive wheels of the truck;
- (b) an electric motor for actuating a pump which supplies hydraulic circuits of the truck;
- (c) a dc power supply for supplying the electric motors, wherein the at least one electric motor for providing the tractive power or both electric motors are asynchronous motors;
- (d) an angular position sensor means for measuring the angular position of the asynchronous motor;
- (e) an angular speed sensor means for measuring the angular speed of the asynchronous motor;
- (f) an electronic control unit connected to the angular position sensor means and the angular speed sensor means, wherein the electronic control unit controls the power input to the asynchronous motor with regard to the required speeds of the asynchronous motor and on the basis of data provided by the angular position sensor means and the angular speed sensor means;
- (g) a plurality of controls of the lift truck connected to an input section of the electronic control unit, wherein the tractive power and the hydraulic circuits supplied by the pump are connected to a sensor device means including the angular position sensor means and the angular speed sensor means to provide feedback data on parameters relating to the operation of the lift truck;
- (h) a two-way connection to an instrument panel connected to the electronic control unit, wherein the instrument panel includes:
- a display,
- a series of indicator lights for displaying operating conditions and parameters of the lift truck as well as alarm situations,
- a set of keys for the input of, and variation of, operating parameters shown by the display, wherein the set of keys include a mode key for displaying on the display a mode "select parameter" or "modify parameter", and two selection and variation keys for selecting the parameter to be varied and for varying the parameter;
- (i) a first microprocessor included in the electronic control unit, wherein the first microprocessor is dedicated to the tractive-power motor;
- (j) a second microprocessor included in the electronic control unit, wherein the second microprocessor is dedicated to the motor for actuating the pump;
- (k) a first memory included in the electronic control unit, wherein the first memory contains the programs that the microprocessors follow and the data that the microprocessors process;
- and
- (l) a second memory included in the electronic control unit, wherein the microprocessor inputs and retrieves data.
13 more elements
Dependencies are inferred from the claim text.