Abstract: A lift truck includes a secondary rechargeable energy storage device on a vertically movable platform that is separate from a primary rechargeable energy storage device on the lift truck's main tractor unit. Wires or hoses for transfer of power or controls between the main tractor unit and the platform are reduced or eliminated. The quantity of energy stored in the secondary rechargeable energy storage device is sufficient to power platform electrical loads for a predetermined amount of time until the platform is lowered. When the platform is lowered, the secondary rechargeable energy storage device is recharged by the primary energy storage device.

Abstract: A control system for controlling motion of a pallet truck vehicle includes three modes of operation for controlling coasting of the vehicle. In a first, constant pressure mode, the vehicle coasts for as long as an activation button is depressed. In a second, time controlled mode, the vehicle coasts for a predetermined period of time. In the third, distance controlled mode, the vehicle coasts for a predetermined distance. Each of these functions can be activated from a remote location using a remote activation device.

Abstract: A plurality of rechargeable and removable batteries are allocated to a plurality of industrial vehicles based on the power delivery capability of each battery and the intensity level at which each vehicle is operated. One of a plurality of ratings is assigned to each industrial vehicle, wherein a rating denotes an operating intensity level. The actual capacity of each battery is measured. A given battery is installed on a particular industrial vehicle in response to the relationship between the rating assigned to that industrial vehicle and the actual capacity of the given battery. Batteries with greater actual capacity are installed on industrial vehicles that are used more intensively. When a battery ages and its actual capacity diminishes, that battery is installed on less intensively used industrial vehicles.

Abstract: Operation of an industrial vehicle, such as one that lifts and transports loads, is controlled based on the weight of a removable battery. A control method involves reading a battery weight value from an electronic memory attached to a battery. That battery weight value is compared to a specified battery weight value for the industrial vehicle. The operation of the industrial vehicle is restricted to less than the normal operating characteristics when the battery weight value is less than the specified battery weight value. For example, the height to which a load can be raised is limited or the speed at which the industrial vehicle is limited when a battery installed on the industrial vehicle weighs less than the specified battery weight for effectively counterbalancing a load.

Abstract: Deterioration of a cable, that connects a battery to an industrial vehicle, is detected by an electronic controller. An electrical parameter, such as voltage, is measured proximate to a connection of the cable to the battery, thereby producing a first measurement. The same electrical parameter also is measured proximate to a connection of the cable to the industrial vehicle, thereby producing a second measurement. The first and second measurements are received at the electronic controller which uses those measurements to produce an indication of deterioration of the cable.

Abstract: A lift truck includes a secondary rechargeable energy storage device on a vertically movable platform that is separate from a primary rechargeable energy storage device on the lift truck's main tractor unit without the use of wires or hoses for transfer of power or controls between the main tractor unit and the platform. The quantity of energy stored in the secondary rechargeable energy storage device is sufficient to power platform electrical loads for a predetermined amount of time until the platform is lowered. When the platform is lowered, the secondary rechargeable energy storage device is recharged by the primary energy storage device.

Abstract: A lift truck power source includes a hybrid power supply including a storage battery, a capacitor bank, and optionally a fuel cell. The capacitor bank stores power produced during regeneration by either the truck traction system or the lift system and delivers current when current demand exceeds that delivered by the fuel cell. The storage battery or fuel cell acts as a main power supply to deliver current at a rate sufficient to power the lift truck. When the fuel cell is the main power supply, the storage battery stores power during times when current demand is less than that delivered by the fuel cell and delivers current at times when current demand is greater than that delivered by the fuel cell. When the storage battery is the main power supply, the fuel cell supplements the power delivered by the storage battery, and can also recharge the storage battery.

Abstract: An industrial vehicle has a controller connected to a plurality of sensors for accumulating information related to operation of the vehicle. The controller employs that information in governing further vehicle operation to reduce the likelihood of damage to the vehicle or a load being transported. The information also is analyzed to determine how efficiently the industrial vehicle and its operator are performing in relation to performance benchmarks for the vehicle and in comparison to other industrial vehicles. Performance of the industrial vehicle can be limited to conserve battery power and restrict recharging the battery to off-peak hours of an electrical utility. When the sensors detect a malfunction of the industrial vehicle, a fault code is produced. A service technician can use that fault code to automatically access service manuals stored in the computer system of the vehicle and obtain information for diagnosing and correcting the malfunction.

Abstract: A control system for controlling motion of a pallet truck vehicle includes three modes of operation for controlling coasting of the vehicle. In a first, constant pressure mode, the vehicle coasts for as long as an activation button is depressed. In a second, time controlled mode, the vehicle coasts for a predetermined period of time. In the third, distance controlled mode, the vehicle coasts for a predetermined distance. Each of these functions can be activated from a remote location using a remote activation device.

Abstract: The present invention features an electric motor control system combination with at least one electric motor having a field winding and an armature winding connected in series. The system also includes a first power terminal, a second power terminal, a current-limiting resistor, and a current sensor. The current-limiting resistor and the current sensor are connected in series between the first power terminal and the second power terminal. A contactor has a contact operable to shunt the current-limiting resistor. A microcomputerized control connected to the contactor and the current sensor governs the contractor to shunt the current-limiting resistor when the electric motor is not in a plugged condition. The contactor is operative when the current sensor detects a substantially zero current through the electric motor.

Abstract: A hydraulic lifting and lowering system for battery-powered lift trucks includes an electronic control system which reduces or limits operator selected lifting commands in accordance with the current being drawn by an electric motor connected to drive a variable-displacement pump, and in accordance with the state-of-charge of the vehicle battery, to control a proportional valve which meters fluid flow to a lift cylinder.