- Backing plate- A circular metal plate that attaches to the drive motor and serves as the attaching point for all of the brake hardware.
- Disk Brake Assembly- A Hydraulic brake system that uses hydraulic oil to increased pressure in the caliper that in turn forces the pistons out of their bore. The pistons press on the brake pads which in turn apply pressure against the brake rotor causing the rotor to slow the rotation of the drive axle. This ultimately stops the machine.
- Brake caliper- A machined assembly that houses the brake pistons and pads. Brake Pucks (Pads)- The equivalent of a brake shoe on a disk brake system. Brake Rotor- A disk which is attached to the drive axle.
- Dead man brake- A brake pedal assembly that applies the truck brake and disables the drive motor when the pedal is released. This prevents the operation of the machine if there is no operator standing on the pedal.
- Electric disc brake- An electrically actuated braking system used in place of a hydraulically actuated brake system. The brake is mounted on the drive motor and a sensor under the brake pedal sends a signal to the brake assembly to apply the brake based on pedal position.
- Master cylinder- A hydraulic device that converts mechanical force into hydraulic force which then actuates the wheel cylinders or caliper pistons to apply the brakes.
- Shoe and lining (brake shoes)- An assembly that consists of a stamped steel plate with a composite friction material bonded to it. The pressure from the wheel cylinder or air chamber forces the brake shoes to spread apart. The force of the bonded material against the brake drum slows the rotation of the drive axle and stops the machine.
- Wheel cylinder or Slave cylinder- A hydraulic cylinder in a drum brake system that transfers the hydraulic force from the master cylinder to the brake shoes through two small pistons in the cylinder.
- Access Modules- This exclusive Crown system acts as the interface between the operator or technician, and the truck electronics system. It allows the truck to have its performance parameters set through the dash display, as well as to display trouble codes.
- Capacitor- An electronic energy storage cell that may be used to maintain steady voltage in an electronic circuit. The capacitor may also act as a filter in the circuit as it can "differentiate" between frequencies.
- Chopper- A motor control device that "chops" up available battery power to regulate motor speed.
- Contactor panel- A flat metal panel on which the contactors are mounted. It is typically comprised of the mounting plate, contactors, electric bus bars, power cables and wiring harnesses.
- Contactors- An electronic switch that uses low amperage control to turn on or off a high amperage load. An electromagnetic coil in the contactor is energized when a specific function- such as direction or hydraulics- is selected. The coil then moves a contact tip or set of tips to open (turn off) or close (turn on) the electric circuit to the specific motor that the contactor controls.
- Control panel- Commonly referred to as the Traction Panel this is a flat metal panel on which the drive control devices are mounted
- Current sensor/ shunt- On SCR control panels this device is typically a strip of metal that has a known resistance. As the current of the circuit flows through this strip the voltage drop from one end of the strip to the other is measured and the current flow is then calculated.
- Hydraulic panel- A flat metal panel on which the hydraulic system control devices are mounted.
- Oscillator card- A printed circuit board that controls the functions of the electronic circuits on SCR controlled trucks.
- PMC control- Programmable Motor Controller is the trade name for a solid-state control box manufactured by Curtis Instruments that controls the operating functions of a specific motor. These units can be programmed to operate the motor under very precise parameters by the use of a hand-held programmer.
- Potentiometer- A variable resistor that is used to control the amount of voltage allowed through an electrical circuit. It is commonly used to control motor speed.
- Rectifier- A solid state semiconductor that behaves like a one-way valve in an electronic circuit. The rectifier allows current to flow in only one direction while blocking current in the opposite direction.
- Resistor control- An electronic control system that uses series of resistors to control motor speeds.
- SCR- A solid-state semiconductor that acts like a switch when it receives an electronic pulse and continues to conduct as long as it remains energized.
- SCR control- An electronic control system that uses Silicon Controlled Rectifiers and a control card to control motor speeds.
- Snubber- A device that controls and filters electrical peaks across a rectifier protecting the circuit.
- Thyristor- See SCR
- Traction panel- A flat metal panel on which the drive motor control devices are mounted. Commonly associated components such as drive motor controllers, bus bars, power cables and wiring harnesses are found on the traction panel assembly.
- Control handle- Used to control the forward and reverse direction, and the hydraulic function of the truck. Control handles are sometimes referred to as "Joysticks" control
- Drive Unit- This assembly acts as the transmission and steering unit for Class II trucks. The drive motor mounts to the upper section of the drive unit and transfers power from the motor to the drive tire through a series of reduction gears. The entire drive motor/ drive unit
- assembly is mounted to the truck chassis on a very large bearing set so that the assembly can turn and steer the truck.
- Elevating section- includes the upright and its components. Refer to Upright section for common upright parts.
- Operator's platform- The structure on which the operator stands and controls the functions of the order picker. The platform moves up and down with the upright to allow the operator access to different levels of storage in a warehouse.
- Outriggers- The front legs on the Class II truck onto which the load wheels are mounted. The outriggers serve to keep the lift balanced so it does not tip forward under load.
- Reach carriage- The portion of a reach truck upright that moves the forks horizontally forward and backward. A hydraulic cylinder and scissor arms allow the carriage to extend and retract into a storage area.
- Single reach and double reach- This determines the length of reach of the fork carriage. Single reach will allow the load to be placed in a single depth pallet rack; the double, or deep reach, will allow the load to be placed into two-deep pallet rack.
- Armature- The rotating part of an electric motor. This part is also referred to as a rotor.
- Commutator- A set of insulated copper contact segments positioned around the armature shaft and connected to the armature coils. The motor brushes transfer the truck battery voltage through the commutator and the armature coils to make the motor turn.
- Brushes- Spring loaded carbon blocks that conduct current between the stationary power wires and the rotating commutator.
- Brush holder- A non-conductive plate, or ring, that holds the carbon brushes in a fixed position above the commutator.
- Drive motor- The large electric motor that is connected to the drive unit to propel the lift truck.
- Hydraulic pump motor- The electric motor that drives, or turns, the hydraulic pump. Sometimes referred to as the lift pump motor.
- Power steering motor- The electric motor that drives, or turns, the hydraulic power steering pump.
- Encoder- Used in electric steering systems this is a rotary device that measures the position of the steering hand wheel or tiller and compares that data to the position of the drive unit assembly. Any variance in the two positions is corrected by the electric steer motor and the truck is steered in this manner.
- Steer cable/chain- On a mechanical steering system these connect the steering hand wheel or tiller to the drive unit assembly to turn the truck.
- Steer motor- A hydraulically actuated motor that turns a steering shaft which then turns the drive unit.
- Steering hand wheel- The part of the steering system that is turned by the operator to make the truck turn in response.
- Steering orbitrol valve- This valve directs hydraulic steering fluid to the steering motor to make the truck turn. This part is commonly referred to as a hydrostatic steer gear, steering hand pump, or torque generator .
Tires and Wheels-
(Load wheels, drive tire, casters)
- Stabilizer/Caster wheel- Used on stand-up rider trucks this wheel assembly consists of a cushion tire and swivel that is mounted below the operator compartment and adjacent to the steer/drive wheel so that the truck is "stabilized", or balanced.